C4-carboxylic acid-substituted tryptamine derivatives and methods of using

ABSTRACT

Disclosed are novel C 4 -carboxylic acid-substituted tryptamine derivative compounds and pharmaceutical and recreational drug formulations containing the same. The pharmaceutical formulations may be used to treat brain neurological disorders.

RELATED APPLICATIONS

This application claims the benefit of United States Provisional U.S.Provisional Application No. 63/321,440 filed Mar. 18, 2022, and U.S.Provisional Application No. 63/347,835 filed Jun. 1, 2022; the entirecontents of Patent Application Nos. 63/321,440 and 63/347,835 are herebyincorporated by reference.

FIELD OF THE DISCLOSURE

The compositions and methods disclosed herein relate to a class ofchemical compounds known as tryptamines. Furthermore, the compositionsand methods disclosed herein relate to C₄-substituted tryptaminederivatives, and, in particular, to C₄-carboxylic acid-substitutedtryptamine derivatives.

BACKGROUND OF THE DISCLOSURE

The following paragraphs are provided by way of background to thepresent disclosure. They are not however an admission that anythingdiscussed therein is prior art or part of the knowledge of a person ofskill in the art.

Tryptamines are a class of chemical compounds that share a commonchemical structure (notably, a fused benzene and pyrrole ring, togetherknown as an indole, and linked to the pyrrole ring, at the third carbonatom, a 2-aminoethyl group), and can be formulated as therapeutic drugcompounds. For example, psilocybin has been evaluated as a drug for itsclinical potential in the treatment of mental health conditions (Daniel,J. et al. Mental Health Clin., 2017; 7(1): 24-28), including to treatanxiety in terminal cancer patients (Grob, C. et al. Arch. Gen.Psychiatry, 2011, 68(1) 71-78) and to alleviate symptoms oftreatment-resistant depression (Cathart-Harris, R. L. et al. LancetPsychiatry, 2016, 3: 619-627). Other known drug compounds within thetryptamine class of compounds include, for example, melatonin,serotonin, bufotenin, dimethyltryptamine (DMT), and psilocin.

It is commonly understood that tryptamine-based drugs can produce theirin vivo therapeutic effects by molecular interaction with macromoleculespresent in human cells, known as receptors. In this respect, in broadterms, specific receptors can be thought of as being located in arelatively fixed anatomical space (e.g., a specific brain tissue).Following administration of a drug, the drug moves through the body tothe receptor to interact therewith, and then back out of the body. It isgenerally desirable that when a tryptamine-based drug is administered,the drug is specifically active at the desired anatomical locationwithin a patient's body, such as, for example, in a specific braintissue and/or at a specific receptor, a 5-hydroxytryptamine (5-HT)receptor, for example. Moreover, it is generally desirable that thespecific molecular interaction between the drug and a receptor, such asa 5-HT receptor, is such that the drug-receptor molecular interactionresults in appropriate modulation of the target receptor.

In many instances the observed pharmacological effect oftryptamine-based drugs is suboptimal. Thus, administration of the drugmay fall short of the desired therapeutic effect (e.g., the successfultreatment of a psychotic disorder) and/or undesirable side effects maybe observed.

The underlying causes for these observed shortcomings in pharmacologicaleffects may be manifold. For example, the administered drug additionallymay interact with receptors other than the target receptor, and/or thespecific molecular interaction between drug and target may not lead tothe desired receptor modulation, and/or the concentration of the drug atthe receptor may be suboptimal. In this respect, known tryptamine-baseddrugs can be said to frequently display suboptimal pharmacodynamic (PD)characteristics, i.e., suboptimal characteristics with respect to thepharmacological effect exerted by the drug on the body. Thus, forexample, the intensity of the drug's effect, the concentration of thedrug at the receptor, and the molecular interactions between the drugand receptor may not be as desired.

Furthermore, as is the case with many pharmaceutical compounds,tryptamine compounds when administered can penetrate multiple tissues bydiffusion, resulting in broad bodily distribution of the drug compound(Bodor, N. et al., 2001, J. Pharmacy and Pharmacology, 53: 889-894).Thus, frequently a substantial proportion of the administered drug failsto reach the desired target receptor. This in turn may necessitate morefrequent dosing of the drug. Such frequent dosing is less convenient toa patient, and, moreover, may negatively affect patient compliance withthe prescribed drug therapy. In addition, generally toxicity associatedwith drug formulations tends to be more problematic as a result of broadbodily distribution of the drug throughout the patient's body sinceundesirable side effects may manifest themselves as a result ofinteraction of the drug with healthy organs.

Furthermore, it is generally desirable that drug compounds exert apharmacological effect for an appropriate period of time. However,tryptamine-based drugs when systemically administered to a patient canexhibit a high blood plasma clearance, typically on the order of minutes(Vitale, A. et al., 2011, J. of Nucl. Med, 52(6), 970-977). Thus, rapiddrug clearance can also necessitate more frequent dosing oftryptamine-based drug formulations. In this respect, known tryptaminecontaining drug formulations can be said to frequently displaysuboptimal pharmacokinetic (PK) characteristics, i.e., suboptimalcharacteristics with respect to movement of the drug through the body toand from the desired anatomical location, including, for example,suboptimal drug absorption, distribution, metabolism, and excretion.

There exists therefore a need in the art for improved tryptaminecompounds.

SUMMARY OF THE DISCLOSURE

The following paragraphs are intended to introduce the reader to themore detailed description, not to define or limit the claimed subjectmatter of the present disclosure.

In one aspect, the present disclosure relates to tryptamines andderivative compounds thereof.

In another aspect, the present disclosure relates to C₄-substitutedtryptamine derivative compounds.

In another aspect, the present disclosure relates to C₄-carboxylicacid-substituted tryptamine derivative compounds.

Accordingly, in one aspect, the present disclosure provides, in at leastone embodiment, in accordance with the teachings herein, a chemicalcompound having chemical formula (I):

wherein R₄ is a carboxylic acid moiety or a derivative thereof; andwherein R_(3a) and R_(3b) are each independently a hydrogen atom, analkyl group, or an aryl group.

In at least one embodiment, in an aspect, the carboxylic acid moiety orderivative thereof can have the chemical formula (II):

wherein R_(4a) is an aryl group, a substituted aryl group, a heteroarylgroup, a substituted heteroaryl group, an alkyl group, a substitutedalkyl group, an amine group, or a substituted amine group.

In at least one embodiment, in an aspect, the aryl group and substitutedaryl group can be a phenyl group and a substituted phenyl group,respectively.

In at least one embodiment, in an aspect, the substituted aryl group canbe a halo-substituted phenyl group.

In at least one embodiment, in an aspect, the alkyl group can be aC₁-C₁₀ alkyl group, in which optionally, at least one carbon atom in thealkyl chain is replaced with an oxygen (O) atom.

In at least one embodiment, in an aspect, the substituted alkyl groupcan be a C₁-C₁₀ alkyl group, wherein the optional substituents are atleast one of halo, C₃-C₆ cycloalkyl, or amino (NH₂).

In at least one embodiment, in an aspect, the substituted alkyl groupcan be a C₁-C₁₀ alkyl group, wherein the optional substituent is C₃-C₆cycloalkane.

In at least one embodiment, in an aspect, the substituted alkyl groupcan be a C₁-C₁₀ alkyl group, wherein the optional substituent iscyclo-propane.

In at least one embodiment, in an aspect, the substituted alkyl groupcan be —CH₂-cyclopropane.

In at least one embodiment, in an aspect, the aryl group can be a phenylgroup in which two substituents on the phenyl group are joined togetherto form an additional 5-7-membered carbocyclic or heterocyclic ring.

In at least one embodiment, in an aspect, the 5-7-membered ring can be amethylene-dioxy ring, an ethylene-dioxy ring or a dihydrofuryl ring.

In at least one embodiment, in an aspect, the substituted aryl group canbe an optionally substituted phenyl group which is substituted with analkoxy group, a substituted alkoxy group, an acetamidyl group or analkoxycarbonyl group.

In at least one embodiment, in an aspect, the alkoxycarbonyl group canbe a methoxycarbonyl (CH₃OC(═O)—).

In at least one embodiment, in an aspect, the alkoxycarbonyl group canbe a substituted heteroaryl-carbonyl group (heteroaryl-O—C(═O)—).

In at least one embodiment, in an aspect, the substituted phenyl groupcan be an O-alkylated phenyl group, in which the phenyl group can besubstituted with one or more O-alkyl groups.

In at least one embodiment, in an aspect, the O-alkyl group can be amethoxy group, an ethoxy group, a propoxy group, an iso-propoxy group,or a butoxy group (n-but, s-but, or t-but).

In at least one embodiment, in an aspect, the O-alkylated phenyl groupcan be O-alkylated by one or more methoxy groups.

In at least one embodiment, in an aspect, the substituted phenyl groupcan be a halogenated phenyl group.

In at least one embodiment, in an aspect, the halogenated phenyl groupcan be a per-fluorinated phenyl.

In at least one embodiment, in an aspect, the substituted phenyl groupcan be a trifluoromethylated phenyl group (—CF₃), or a trifluoromethoxyphenyl group (—OCF₃).

In at least one embodiment, in an aspect, the substituted aryl group canbe a substituted phenyl group having one or more substituents which arehalo, alkoxy, alkyl, halo-substituted alkyl, or halo-substituted alkoxy.

In at least one embodiment, in an aspect, the phenyl group can besubstituted with one or more of a trifluoromethoxy group, a methoxygroup, or a halogen atom.

In at least one embodiment, in an aspect, R_(4a) can be a substitutedpyridine group.

In at least one embodiment, in an aspect, the substituted pyridine groupcan be an O-alkylated pyridine group, an O-arylated pyridine group, or ahalogenated pyridine group.

In at least one embodiment, in an aspect, the O-alkylated pyridine groupcan be O-alkylated by one or more methoxy groups.

In at least one embodiment, in an aspect, the O-alkylated pyridine groupcan be O-alkylated by one or more methoxy groups and one or more halogenatoms.

In at least one embodiment, in an aspect, the pyridine group can besubstituted with a O-aryl group.

In at least one embodiment, in an aspect, the O-aryl group can be anO-phenyl group.

In at least one embodiment, in an aspect, the substituted aryl group canbe a substituted phenyl group which is substituted by a carboxylatemoiety.

In at least one embodiment, in an aspect, the substituted amine groupcan be —NH—CH₂R, where R is an organic radical.

In at least one embodiment, in an aspect, in the compound havingchemical formula (I) the compound can be selected from the groupconsisting of C(I), C(II), C(III), C(IV), C(V), C(VI), C(VII), C(VIII),C(IX), C(X), C(XI), C(XII), C(XIII), C(XIV), C(XV), C(XVI), C(XVII),C(XVIII), C(XIX), C(XX), C(XXI), C(XXII), C(XXIII), C(XXIV), C(XXV),C(XXVI), C(XXVII), C(XXVIII), C(XXIX), C(XXX), C(XXXI), C(XXXII),C(XXXIII), C(XXXIV), C(XXXV), C(XXXVI), C(XXXVII), C(XXXVIII), C(XXXIX),C(XL), C(XLI), C(XLII), and C(XLIII):

In another aspect, the present disclosure relates to pharmaceutical andrecreational drug formulations comprising C₄-carboxylic acid-substitutedtryptamine derivative compounds. Accordingly, in one aspect, the presentdisclosure provides, in at least one embodiment, a pharmaceutical orrecreational drug formulation comprising an effective amount of achemical compound having a formula (I):

-   -   wherein R₄ is a carboxylic acid moiety or derivative thereof;        and    -   wherein R_(3a) and R_(3b) are each independently a hydrogen        atom, an alkyl group, or an aryl group, together with a        pharmaceutically acceptable excipient, diluent, or carrier.

In at least one embodiment, in an aspect, the pharmaceutical formulationcan be a pro-drug pharmaceutical formulation, wherein the compoundhaving formula (I) is in vivo hydrolyzed to form a compound havingchemical formula (VI):

wherein R_(3a) and R_(3b) are each independently a hydrogen atom, analkyl group, or an aryl group.

In another aspect, the present disclosure relates to methods oftreatment of brain neurological disorders. Accordingly, the presentdisclosure further provides, in one embodiment, a method for treating abrain neurological disorder, the method comprising administering to asubject in need thereof a pharmaceutical formulation comprising achemical compound having a formula (I):

-   -   wherein R₄ is a carboxylic acid moiety or derivative thereof;    -   wherein R_(3a) and R_(3b) are each independently a hydrogen        atom, an alkyl group, or an aryl group, wherein the        pharmaceutical formulation is administered in an effective        amount to treat the brain neurological disorder in the subject.

In at least one embodiment, in an aspect, upon administration thecompound having formula (I) can interact with a receptor in the subjectto thereby modulate the receptor and exert a pharmacological effect.

In at least one embodiment, in an aspect, the receptor can be a5-HT_(1A) receptor, a 5-HT_(2A) receptor, a 5-HT_(1B) receptor, a5-HT_(2B) receptor, a 5-HT_(3A) receptor, an ADRA1A receptor, an ADRA2Areceptor, a CHRM1 receptor, a CHRM2 receptor, a CNR1 receptor, a DRD1receptor, a DRD2S receptor, or an OPRD1 receptor.

In at least one embodiment, in an aspect, upon administration thecompound having formula (I) can interact with an enzyme or transmembranetransport protein in the subject to thereby modulate the enzyme ortransmembrane transport protein and exert a pharmacological effect.

In at least one embodiment, in an aspect, the enzyme can be monoamineoxidase A (MOA-A), and the transmembrane transport protein can be adopamine active transporter (DAT), a norephedrine transporter (NET), ora serotonin transporter (SERT) transmembrane transport protein.

In at least one embodiment, in an aspect, upon administration thecompound having formula (I) can be in vivo hydrolyzed to form a compoundhaving chemical formula (VI):

-   -   wherein R_(3a) and R_(3b) are each independently a hydrogen        atom, an alkyl group, or an aryl group,    -   and wherein the compound having chemical formula (VI) interacts        with a receptor to thereby modulate the receptor in the subject        and exert a pharmacological effect.

In at least one embodiment, in an aspect, the receptor can be 5-HT_(1A)receptor, a 5-HT_(2A) receptor, a 5-HT_(1B) receptor, a 5-HT_(2B)receptor, a 5-HT_(3A) receptor, an ADRA1A receptor, an ADRA2A receptor,a CHRM1 receptor, a CHRM2 receptor, a CNR1 receptor, a DRD1 receptor, aDRD2S receptor, or an OPRD1 receptor.

In at least one embodiment, in an aspect, the disorder can be a5-HT_(1A) receptor-mediated disorder, a 5-HT_(2A) receptor-mediateddisorder, a 5-HT_(1B) receptor-mediated disorder, a 5-HT_(2B)receptor-mediated disorder, a 5-HT_(3A) receptor-mediated disorder, anADRA1A receptor-mediated disorder, an ADRA2A receptor-mediated disorder,a CHRM1 receptor-mediated disorder, a CHRM2 receptor-mediated disorder,a CNR1 receptor-mediated disorder, a DRD1 receptor-mediated disorder, aDRD2S receptor-mediated disorder, or an OPRD1 receptor-mediateddisorder.

In at least one embodiment, in an aspect, a dose can be administered ofabout 0.001 mg to about 5,000 mg.

In another aspect, the present disclosure provides, in at least oneembodiment, a method for modulating (i) a receptor selected from5-HT_(1A) receptor, a 5-HT_(2A) receptor, a 5-HT_(1B) receptor, a5-HT_(2B) receptor, a 5-HT_(3A) receptor, an ADRA1A receptor, an ADRA2Areceptor, a CHRM1 receptor, a CHRM2 receptor, a CNR1 receptor, a DRD1receptor, a DRD2S receptor, or an OPRD1 receptor; (ii) an enzyme, theenzyme being MOA-1; or (iii) a transmembrane transport protein selectedfrom a dopamine active transporter (DAT), a norephedrine transporter(NET) or a serotonin transporter (SERT) transmembrane transport protein,the method comprising contacting (i) the 5-HT_(1A) receptor, the5-HT_(2A) receptor, the 5-HT_(1B) receptor, the 5-HT_(2B) receptor, the5-HT_(3A) receptor, the ADRA1A receptor, the ADRA2A receptor, the CHRM1receptor, the CHRM2 receptor, the CNR1 receptor, the DRD1 receptor, theDRD2S receptor, or the OPRD1 receptor; (ii) MOA-1; or (iii) the dopamineactive transporter (DAT), the norephedrine transporter (NET), or theserotonin transporter (SERT) transmembrane transport protein with achemical compound having a formula (I):

-   -   wherein R₄ is a carboxylic acid moiety or derivative thereof;        and    -   wherein R_(3a) and R_(3b) are each independently a hydrogen        atom, an alkyl group, or an aryl group, under reaction        conditions sufficient to modulate (i) the 5-HT_(1A) receptor,        the 5-HT_(2A) receptor, the 5-HT_(1B) receptor, the 5-HT_(2B)        receptor, the 5-HT_(3A) receptor, the ADRA1A receptor, the        ADRA2A receptor, the CHRM1 receptor, the CHRM2 receptor, the        CNR1 receptor, the DRD1 receptor, the DRD2S receptor, or the        OPRD1 receptor; (ii) MOA-1; or (iii) the dopamine active        transporter (DAT), the norephedrine transporter (NET), or the        serotonin transporter (SERT) transmembrane transport protein.

In at least one embodiment, in an aspect, the reaction conditions can bein vitro reaction conditions.

In at least one embodiment, in an aspect, the reaction conditions can bein vivo reaction conditions.

In another aspect, the present disclosure relates to methods of makingC₄-carboxylic acid-substituted tryptamine derivative compounds.Accordingly, disclosed herein are methods of making a chemical compoundhaving chemical formula (I):

-   -   wherein R₄ is a carboxylic acid moiety or a derivative thereof;        and    -   wherein R_(3a) and R_(3b) are each independently a hydrogen        atom, an alkyl group, or an aryl group, wherein the method        involves the performance of at least one chemical synthesis        reaction selected from the reactions depicted in FIG. 3A (i), 3A        (ii), 4A, 5A, 6A, 7A, 8A, 9A, or 10A.

In at least one embodiment, in an aspect, the compound having chemicalformula (I) can be a compound having formula C(V):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 3A (i) or, FIG. 3A (ii).

In at least one embodiment, in an aspect, the compound having chemicalformula (I) can be a compound having formula C(VI):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 4A.

In at least one embodiment, in an aspect, the compound having chemicalformula (I) can be a compound having formula C(VII):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 5A.

In at least one embodiment, in an aspect, the compound having chemicalformula (I) can be a compound having formula C(III):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 6A.

In at least one embodiment, in an aspect, the compound having chemicalformula (I) can be a compound having formula C(XLIII):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 7A.

In at least one embodiment, in an aspect, the compound having chemicalformula (I) can be a compound having formula C(I):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 8A.

In at least one embodiment, in an aspect, the compound having chemicalformula (I) can be a compound having formula C(XX):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 9A.

In at least one embodiment, in an aspect, the compound having chemicalformula (I) can be a compound having formula C(IV):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 10A.

In another aspect, the present disclosure relates to uses ofC₄-carboxylic acid-substituted tryptamine derivative compounds.Accordingly, the present disclosure further provides, in at least oneembodiment, a use of a chemical compound having a formula (I):

-   -   wherein R₄ is a carboxylic acid moiety or derivative thereof;    -   wherein R_(3a) and R_(3b) are each independently a hydrogen        atom, an alkyl group, or an aryl group, in the manufacture of a        pharmaceutical or recreational drug formulation.

In at least one embodiment, the manufacture can comprise formulating thechemical compound with a pharmaceutically acceptable excipient, diluent,or carrier.

In another aspect the present disclosure provides, in at least oneembodiment, a use of a chemical compound having a formula (I):

-   -   wherein R₄ is a carboxylic acid moiety or derivative thereof;    -   wherein R_(3a) and R_(3b) are each independently a hydrogen        atom, an alkyl group, or an aryl group, together with a        pharmaceutically acceptable diluent, carrier, or excipient as a        pharmaceutical or recreational drug formulation.

In at least one embodiment, in aspect, the pharmaceutical drug is a drugfor the treatment of a brain neurological disorder.

Other features and advantages will become apparent from the followingdetailed description. It should be understood, however, that thedetailed description, while indicating preferred implementations of thedisclosure, are given by way of illustration only, since various changesand modifications within the spirit and scope of the disclosure willbecome apparent to those of skill in the art from the detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure is in the hereinafter provided paragraphs described, byway of example, in relation to the attached figures. The figuresprovided herein are provided for a better understanding of the exampleembodiments and to show more clearly how the various embodiments may becarried into effect. The figures are not intended to limit the presentdisclosure.

FIG. 1 depicts the chemical structure of tryptamine.

FIG. 2 depicts a certain prototype structure of tryptamine andtryptamine derivative compounds, namely an indole. Certain carbon andnitrogen atoms may be referred to herein by reference to their positionwithin the indole structure, i.e., N₁, C₂, C₃ etc. The pertinent atomnumbering is shown.

FIGS. 3A (i), 3A (ii), 3B, 3C, 3D, 3E, 3F, 3G, 3H, 3I, 3J, 3K, 3L, 3M(i), 3M (ii), 3M (iii), 3N (i), 3N (ii), 3O (i), 3O (ii), 3O (iii), 3P,3Q, 3R, 3S (i), and 3S (ii) depict an example chemical reaction to makean example chemical compound provided by the present disclosure, namelya compound having chemical formula C(V) (FIGS. 3A (i) and 3A (ii)) (thecompound having chemical formula C(V) is referred to as compound (2) inFIGS. 3A (i) and 3A (ii)), and various graphs representing certainexperimental results (FIGS. 3B-3S (ii)), notably graphs obtained in theperformance experimental assays to evaluate the efficacy of an examplecompound a compound having chemical formula C(V), notably a cellviability assay (FIGS. 3B and 3C); a saturation binding assay for[³H]ketanserin at the 5-HT_(2A) receptor (FIG. 3D); a competition assayfor psilocin as a positive control (binding) (FIG. 3E); a competitionassay for psilocybin and tryptophan as a control and negative control(no binding), respectively (FIG. 3F); a competition assay for a compoundwith formula C(V), designated “C-V” (FIG. 3G); a cAMP assay in thepresence of increasing forskolin concentrations in +5HT_(1A) cells and−5HT_(1A) cells (FIG. 3H); a cAMP assay in the presence of varyingconcentrations of tryptophan in +5HT_(1A) cells and −5HT_(1A) cells with4 μM forskolin (FIG. 3I); a cAMP assay in the presence of varyingconcentrations of psilocin in +5HT_(1A) cells and −5HT_(1A) cellsstimulated with 4 μM forskolin (FIG. 3J); a cAMP assay in the presenceof varying concentrations of serotonin in +5HT_(1A) cells and −5HT_(1A)cells stimulated with 4 μM forskolin (FIG. 3K); a cAMP assay in thepresence of varying concentrations of the compound having chemicalformula C(V), designated “C-V” in +5HT_(1A) cells and −5HT_(1A) cellswith 4 μM forskolin (FIG. 3L); psilocybin metabolic conversion assays(FIGS. 3M (i)-3M (iii)); assay controls for psilocin metabolic releaseassays (FIGS. 3N (i)-3N (ii)); metabolic stability assays for a compoundwith formula C(V) (FIGS. 3O (i)-3O (iii)); and drug-induced Head TwitchResponse (HTR) assays using the compound having formula C(V), designated“C-V” (FIG. 3P); mouse PK studies analyzing plasma psilocybin levelsafter 1 mg/kg i.v. dose of psilocybin (FIG. 3Q); mouse PK studiesanalyzing plasma psilocin levels after oral dosing of various levels ofpsilocybin. (FIG. 3R): and mouse PK studies using a chemical compoundhaving formula C(V) (FIGS. 3S (i) and 3S (ii)).

FIGS. 4A, 48, 4C, 4D, 4E, 4F (i), 4F(ii), 4F (iii), 4G, FIGS. 4H (i),and 4H (ii) depict an example chemical reaction to make an examplechemical compound provided by the present disclosure, namely a compoundhaving chemical formula C(VI), (FIG. 4A) (the compound having chemicalformula C(VI) is referred to as compound (3) in FIG. 4A), and variousgraphs representing certain experimental results (FIGS. 4B-4H (ii)),notably graphs obtained in the performance experimental assays toevaluate the efficacy of an example compound a compound having chemicalformula C(VI), notably a cell viability assay (FIGS. 4B and 4C); acompetition assay for a compound with formula C(VI), designated “C-VI”(FIG. 4D); a cAMP assay in the presence of varying concentrations of thecompound having chemical formula C(VI), designated “C-VI” in +5HT_(1A)cells and −5HT_(1A) cells with 4 μM forskolin (FIG. 4E); metabolicstability assays and assays to evaluate the capacity of assayedmolecules to release psilocin under various in vitro conditions (FIGS.4F (i)-4F (iii)); Drug-induced Head Twitch Response (HTR) assays usingthe compound having formula C(VI), designated “C-VI” (FIG. 4G); andmouse PK studies using a chemical compound having formula C(VI) (FIGS.4H (i) and 4H (ii)).

FIGS. 5A, 5B, 5C, 5D, 5E (i), 5E (ii), and 5F depict an example chemicalreaction to make an example chemical compound provided by the presentdisclosure, namely a compound having chemical formula C(VII) (FIG. 5A)(the compound having chemical formula C(VII) is referred to as compound(4) in FIG. 5A), and various graphs representing certain experimentalresults (FIGS. 5B-5F (ii)), notably, graphs obtained in the performanceexperimental assays to evaluate the efficacy of an example compound acompound having chemical formula C(VII), notably a cell viability assay(FIG. 5B); a competition assay for a compound with formula C(VII),designated “C-VII” (FIG. 5C); a CAMP assay in the presence of varyingconcentrations of the compound having chemical formula C(VII),designated “C-VII” in +5HT_(1A) cells and −5HT_(1A) cells with 4 μMforskolin (FIG. 5D); metabolic stability assays for compound withformula C(VII), designated “C-VII”; (FIGS. 5E (i) and 5E (ii)); andDrug-induced Head Twitch Response (HTR) assays using the compound havingformula C(VII), designated “C-VII” (FIG. 5F).

FIGS. 6A, 6B, 6C, 6D, 6E, 6F (i), 6F (ii), and 6G depict an examplechemical reaction to make an example chemical compound provided by thepresent disclosure, namely a compound having chemical formula C(III)(FIG. 6A) (the compound having chemical formula C(III) is referred to ascompound (11) in FIG. 6A), and various graphs representing certainexperimental results (FIGS. 6B-6G), notably graphs obtained in theperformance experimental assays to evaluate the efficacy of an examplecompound a compound having chemical formula C(III), notably a cellviability assay (FIGS. 6B and 6C); a competition assay for a compoundwith formula C(III), designated “C-III” (FIG. 6D); a cAMP assay in thepresence of varying concentrations of the compound having chemicalformula C(III), designated “C-III” in +5HT_(1A) cells and −5HT_(1A)cells with 4 μM forskolin (FIG. 6E); metabolic stability assays andassays to evaluate the capacity of assayed molecules to release psilocinunder various in vitro conditions (FIGS. 6F (i)-6F (ii)); andDrug-induced Head Twitch Response (HTR) assays using the compound havingformula C(III), designated “C-III” (FIG. 6G);

FIGS. 7A, 7B, 7C, 7D, 7E, 7F (i), and 7F (ii), depict an examplechemical reaction to make an example chemical compound provided by thepresent disclosure, namely a compound having chemical formula C(XLIII),(FIG. 7A) (the compound having chemical formula C(XLIII) is referred toas compound (13) in FIG. 7A), and various graphs representing certainexperimental results (FIGS. 7B-7F (ii)), notably graphs obtained in theperformance experimental assays to evaluate the efficacy of an examplecompound a compound having chemical formula C(XLIII), notably a cellviability assay (FIGS. 7B and 7C); a competition assay for a compoundwith formula C(XLIII), designated “C-XLIII” (FIG. 7D); a cAMP assay inthe presence of varying concentrations of the compound having chemicalformula C(XLIII), designated “C-XLIII” in +5HT_(1A) cells and −5HT_(1A)cells with 4 μM forskolin (FIG. 7E); and metabolic stability assays andassays to evaluate the capacity of assayed molecules to release psilocinunder various in vitro conditions (FIGS. 7F (i)-7F (ii).

FIGS. 8A, 8B, 8C, 8D, 8E, 8F (i), 8F (ii), 8G, 8H, 8I (i), and 8I (ii)depict an example series of chemical reactions to make an examplechemical compound provided by the present disclosure, namely a compoundhaving chemical formula C(I) (FIG. 8A) (the compound having chemicalformula C(I) is referred to as compound (8) in FIG. 8A), and variousgraphs representing certain experimental results (FIGS. 8B-8I (ii)),notably graphs obtained in the performance experimental assays toevaluate the efficacy of an example compound a compound having chemicalformula C(I), notably a cell viability assay (FIGS. 8B and 8C); acompetition assay for a compound with formula C(I), designated “C-I”(FIG. 8D); a cAMP assay in the presence of varying concentrations of thecompound having chemical formula C(I), designated “C-I” in +5HT_(1A)cells and −5HT_(1A) cells with 4 μM forskolin (FIG. 8E); metabolicstability assays and assays to evaluate the capacity of assayedmolecules to release psilocin under various in vitro conditions (FIGS.8F (i)-8F (ii)); Drug-induced Head Twitch Response (HTR) assays usingthe compound having formula C(I), designated “C-I” (FIG. 8G); mouse PKstudies using a chemical compound having formula C(I) administered invarious amounts and using various administration modalities (FIG. 8H);and mouse PK studies using a chemical compound having formula C(I)(FIGS. 8I (i) and 8I (ii)).

FIGS. 9A, 9B, 9C, 9D, 9E, 9F (i), 9F (ii), 9G, 9H, 9I (i), and 9I (ii)depict an example chemical reaction to make an example chemical compoundprovided by the present disclosure, namely a compound having chemicalformula C(XX) (FIG. 9A) (the compound having chemical formula C(XX) isreferred to as compound (2) in FIG. 9A), and various graphs representingcertain experimental results (FIGS. 9B-9I (ii)), notably graphs obtainedin the performance experimental assays to evaluate the efficacy of anexample compound a compound having chemical formula C(XX), notably acell viability assay (FIGS. 9B and 9C); a competition assay for acompound with formula C(XX), designated “C-XX” (FIG. 9D); a cAMP assayin the presence of varying concentrations of the compound havingchemical formula C(XX), designated “C-XX” in +5HT_(1A) cells and−5HT_(1A) cells with 4 μM forskolin (FIG. 9E); metabolic stabilityassays and assays to evaluate the capacity of assayed molecules torelease psilocin under various in vitro conditions (FIGS. 9F (i)-9F(ii)); Drug-induced Head Twitch Response (HTR) assays using the compoundhaving formula C(XX), designated “C-XX” (FIG. 9G); mouse PK studiesusing a chemical compound having formula C(XX) administered in variousamounts and using various administration modalities (FIG. 9H); and mousePK studies using a chemical compound having formula C(XX) (FIGS. 9I (i)and 9I (ii)).

FIGS. 10A, 10B, 10C, 10D, 10E, 10F (i), 10F (ii), 10G, 10H (i), and 10H(ii) depict an example chemical reaction to make an example chemicalcompound provided by the present disclosure, namely a compound havingchemical formula C(IV), (FIG. 10A) (the compound having chemical formulaC(IV) is referred to as compound (2) in FIG. 10A), and various graphsrepresenting certain experimental results (FIGS. 10B-10H (ii)), notablygraphs obtained in the performance experimental assays to evaluate theefficacy of an example compound a compound having chemical formulaC(IV), notably a cell viability assay (FIGS. 10B and 10C); a competitionassay for a compound with formula C(IV), designated “C-IV” (FIG. 10D); acAMP assay in the presence of varying concentrations of the compoundhaving chemical formula C(IV), designated “C-IV” in +5HT_(1A) cells and−5HT_(1A) cells with 4 μM forskolin (FIG. 10E); metabolic stabilityassays and assays to evaluate the capacity of assayed molecules torelease psilocin under various in vitro conditions (FIGS. 10F (i)-10F(ii)); Drug-induced Head Twitch Response (HTR) assays using the compoundhaving formula C(IV), designated “C-IV” (FIG. 10G), and mouse PK studiesusing a chemical compound having formula C(IV) (FIGS. 10H (i) and 10H(ii)).

The figures together with the following detailed description makeapparent to those skilled in the art how the disclosure may beimplemented in practice.

DETAILED DESCRIPTION

Various compositions, systems or processes will be described below toprovide an example of an embodiment of each claimed subject matter. Noembodiment described below limits any claimed subject matter and anyclaimed subject matter may cover processes, compositions or systems thatdiffer from those described below. The claimed subject matter is notlimited to compositions, processes or systems having all of the featuresof any one composition, system or process described below or to featurescommon to multiple or all of the compositions, systems or processesdescribed below. It is possible that a composition, system, or processdescribed below is not an embodiment of any claimed subject matter. Anysubject matter disclosed in a composition, system or process describedbelow that is not claimed in this document may be the subject matter ofanother protective instrument, for example, a continuing patentapplication, and the applicant(s), inventor(s) or owner(s) do not intendto abandon, disclaim or dedicate to the public any such subject matterby its disclosure in this document.

As used herein and in the claims, the singular forms, such “a”, “an” and“the” include the plural reference and vice versa unless the contextclearly indicates otherwise. Throughout this specification, unlessotherwise indicated, “comprise,” “comprises” and “comprising” are usedinclusively rather than exclusively, so that a stated integer or groupof integers may include one or more other non-stated integers or groupsof integers.

Various compositions, systems or processes will be described below toprovide an example of an embodiment of each claimed subject matter. Noembodiment described below limits any claimed subject matter and anyclaimed subject matter may cover processes, compositions or systems thatdiffer from those described below. The claimed subject matter is notlimited to compositions, processes or systems having all of the featuresof any one composition, system or process described below or to featurescommon to multiple or all of the compositions, systems or processesdescribed below. It is possible that a composition, system, or processdescribed below is not an embodiment of any claimed subject matter. Anysubject matter disclosed in a composition, system or process describedbelow that is not claimed in this document may be the subject matter ofanother protective instrument, for example, a continuing patentapplication, and the applicant(s), inventor(s) or owner(s) do not intendto abandon, disclaim or dedicate to the public any such subject matterby its disclosure in this document.

When ranges are used herein for physical properties, such as molecularweight, or chemical properties, such as chemical formulae, allcombinations and sub-combinations of ranges and specific embodimentstherein are intended to be included. Other than in the operatingexamples, or where otherwise indicated, all numbers expressingquantities of ingredients or reaction conditions used herein should beunderstood as modified in all instances by the term “about.” The term“about” when referring to a number or a numerical range means that thenumber or numerical range referred to is an approximation withinexperimental variability (or within statistical experimental error), andthus the number or numerical range may vary between 1% and 15% of thestated number or numerical range, as will be readily recognized bycontext. Furthermore, any range of values described herein is intendedto specifically include the limiting values of the range, and anyintermediate value or sub-range within the given range, and all suchintermediate values and sub-ranges are individually and specificallydisclosed (e.g., a range of 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.90, 4,and 5). Similarly, other terms of degree such as “substantially” and“approximately” as used herein mean a reasonable amount of deviation ofthe modified term such that the end result is not significantly changed.These terms of degree should be construed as including a deviation ofthe modified term if this deviation would not negate the meaning of theterm it modifies.

Unless otherwise defined, scientific and technical terms used inconnection with the formulations described herein shall have themeanings that are commonly understood by those of ordinary skill in theart. The terminology used herein is for the purpose of describingparticular embodiments only, and is not intended to limit the scope ofthe present invention, which is defined solely by the claims.

All publications, patents and patent applications are hereinincorporated by reference in their entirety to the same extent as ifeach individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by referencein its entirety.

Terms and Definitions

The term “tryptamine” refers to a chemical compound having the structureset forth in FIG. 1 .

The term “indole prototype structure” refers to the chemical structureshown in FIG. 2 . It is noted that specific carbon atoms and a nitrogenatom in the indole prototype structure are numbered. Reference may bemade to these carbon and nitrogen numbers herein, for example C₂, C₄,N₁, and so forth. Furthermore, reference may be made to chemical groupsattached to the indole prototype structure in accordance with the samenumbering, for example, R₄ and R₆ reference chemical groups attached tothe C₄ and C₆ atom, respectively. In addition, R_(3a) and R_(3b), inthis respect, reference chemical groups extending from the ethyl-aminogroup extending in turn from the C₃ atom of the prototype indolestructure.

The term “tryptamine derivative”, as used herein, refers to compoundsthat can be derivatized from tryptamine, wherein such compounds includean indole prototype structure and a C₃ ethylamine or ethylaminederivative group having the formula (VII):

wherein R₄, is a substituent (any atom or group other than a hydrogenatom) comprising a carboxylic acid moiety or a derivative thereof, andwherein R_(3a) and R_(3b) are each independently a hydrogen atom, analkyl group, or an aryl group. Thus, tryptamine derivative compoundsinclude compounds containing a substituent at C₄, as defined. Additionalother atoms, such as N₁, may also be substituted. Moreover, in thisrespect, tryptamine derivatives containing a substituent atom or groupat e.g., C₄ may be referred to as C₄-substituted tryptamine derivatives.In chemical formula (VII), R₄, can, for example, be a carboxylic acidmoiety or derivative thereof, and the tryptamine derivative may bereferred to as a C₄-carboxylic acid-substituted tryptamine derivative.

The terms “carboxyl group”, “carboxyl”, “carboxylic acid” and “carboxy”,as used herein, refer to a molecule containing one atom of carbon bondedto an oxygen atom and a hydroxy group and having the formula —COOH. Acarboxyl group includes a deprotonated carboxyl group, i.e., a carboxylion, having the formula —COO⁻. In its deprotonated form a carboxyl groupmay form a carboxyl salt, for example, a sodium or potassium carboxylsalt, or an organic carboxyl salt.

The term “carboxylic acid moiety or derivative thereof”, as used herein,refers to a modulated carboxyl group wherein the hydroxy group of thecarboxyl group has been substituted by another atom or group. Thus, acarboxylic acid moiety or derivative thereof includes a group havingchemical formula (X):

wherein, wherein R₄′, for example, is an aryl group, a substituted arylgroup, a heteroaryl group, a substituted heteroaryl group, an alkylgroup, a substituted alkyl group, an amine group, or a substituted aminegroup. It is noted that the partially bonded oxygen atom of the grouphaving formula (X) can be bonded to another entity, including, forexample, to the C₄ atom of tryptamine.

The terms “halogen”, “halogenated” and “halo-”, as used herein, refer tothe class of chemical elements consisting of fluorine (F), chlorine(Cl), bromine (Br), and iodine (I). Accordingly, halogenated compoundscan refer to “fluorinated”, “chlorinated”, “brominated”, or “iodinated”compounds.

The terms “hydroxy group”, and “hydroxy”, as used herein, refers to amolecule containing one atom of oxygen bonded to one atom of hydrogenand having the formula —OH. A hydroxy group through its oxygen atom maybe chemically bonded to another entity.

The term “amino group” and “amino”, as used herein, refers to a moleculecontaining one atom of nitrogen bonded to hydrogen atoms and having theformula —NH₂. An amino group also may be protonated and having theformula —NH₃ ⁺.

The term “alkyl group”, as used herein, refers to a straight and/orbranched chain, saturated alkyl radical containing from one to “p”carbon atoms (“C1-Cp-alkyl”) and includes, depending on the identity of“p”, methyl, ethyl, propyl, isopropyl, n-butyl, s-butyl, isobutyl,t-butyl, 2,2-dimethylbutyl, n-pentyl, 2-methylpentyl, 3-methylpentyl,4-methylpentyl, n-hexyl, and the like, where the variable p is aninteger representing the largest number of carbon atoms in the alkylradical. Alkyl groups further include hydrocarbon groups arranged in achain having the chemical formula —CnH2n+1, including, withoutlimitation, methyl groups (—CH3), ethyl groups (—C2H5), propyl groups(—C3H7), and butyl groups (—C4H9).

The term “alkylene”, as used herein, refers to a divalent alkyl.

The term “cyclo-alkyl”, as used herein, refers to cyclo-alkyl groups,including (C₃-C₂₀), (C₃-C₁₀), and (C₃-C₆) cyclo-alkyl groups, andincludes saturated and partially saturated cyclo-alkyl groups, furtherincluding cyclo-propane, cyclo-butane, cyclo-pentane, cyclo-hexane,cyclo-heptane, cyclopentene and cyclohexene.

The terms “O-alkyl group”, and “alkoxy group”, as used hereininterchangeably, refer to a hydrocarbon group arranged in a chain havingthe chemical formula —O—C_(n)H_(2n+1). O-alkyl groups include, withoutlimitation, O-methyl groups (—O—CH₃) (i.e., methoxy), O-ethyl groups(—O—C₂H₅) (i.e., ethoxy), O-propyl groups (—O—C₃H₇) (i.e., propoxy) andO-butyl groups (—O—C₄H₉) (i.e., butoxy).

The term “aryl group”, as used herein, refers to a hydrocarbon grouparranged in an aromatic ring and can, for example, be a C₆-C₁₄-aryl, aC₆-C₁₀-aryl. Aryl groups further include phenyl, naphthyl,tetrahydronaphthyl, phenanthrenyl, biphenylenyl, indanyl, tolyl, xylyl,or indenyl groups, and the like.

The term “hetero”, as used herein (e.g., “heterocyle”, “heteroaryl”,“alkyl-heteroaryl”), means a saturated or partially saturated oraromatic cyclic group, in which one or two ring atoms are a heteroatomselected from N, O, or S, the remaining ring atoms being C. Includedare, for example, (C₃-C₂₀), (C₃-C₁₀), and (C₃-C₆) cyclic groupscomprising one or two hetero atoms selected from O, S, or N.Furthermore, the saturated, unsaturated, or aromatic cyclic group can beoptionally fused to an aryl or heteroaryl ring, or to a cyclo-alkylring.

The term “alcohol group” or “hydroxylalkyl”, as used herein, refers to ahydrocarbon group arranged in a chain having the chemical formulaC_(n)H_(n+1)OH. Depending on the carbon chain, length specific alcoholgroups may be termed a methanol group (n=1) or hydroxymethyl, an ethanolgroup (n=2) or hydroxyethyl, a propanol group (n=3) or hydroxypropyl, abutanol group (n=4) or hydroxybutyl etc.

The term “receptor”, as used herein, refers to a protein present on thesurface of a cell, or in a cell not associated with a cellular surface(e.g., a soluble receptor) capable of mediating signaling to and/or fromthe cell, or within the cell and thereby affect cellular physiology.Example receptors include, 5-HT_(1A) receptors, 5-HT_(1B) receptors,5-HT_(2A) receptors, and “5-HT_(2B) receptors”, and so on. In thisrespect, “signaling” refers to a response in the form of a series ofchemical reactions which can occur when a molecule, including, forexample, the C₄-substituted tryptamine derivatives disclosed herein,interacts with a receptor. Signaling generally proceeds across acellular membrane and/or within a cell, to reach a target molecule orchemical reaction, and results in a modulation in cellular physiology.Thus, signaling can be thought of as a transduction process by which amolecule interacting with a receptor can modulate cellular physiology,and, furthermore, signaling can be a process by which molecules inside acell can be modulated by molecules outside a cell. Signaling andinteractions between molecules and receptors, including for example,affinity, binding efficiency, and kinetics, can be evaluated through avariety of assays, including, for example, assays known as receptorbinding assays (for example, radioligand binding assays, such as e.g.,[H]ketanserin assays may be used to evaluate receptor 5-HT_(2A) receptoractivity), competition assays, and saturation binding assays, and thelike.

The term “5-HT_(1A) receptor”, as used herein, refers to a subclass of afamily of receptors for the neurotransmitter and peripheral signalmediator serotonin. 5-HT_(1A) receptors can mediate a plurality ofcentral and peripheral physiologic functions of serotonin. Ligandactivity at 5-HT_(1A) is generally not associated with hallucination,although many hallucinogenic compounds are known to modulate 5-HT_(1A)receptors to impart physiological responses (Inserra et al., 2020,Pharmacol. Rev 73: 202). 5-HT_(1A) receptors are implicated in variousbrain neurological disorders, including depression and anxiety,schizophrenia, and Parkinson's disease (Behav. Pharm. 2015, 26:45-58).

The term “5-HT_(1B) receptor”, as used herein, refers to a subclass of afamily of receptors for the neurotransmitter and peripheral signalmediator serotonin. 5-HT_(1B) receptors can mediate a plurality ofcentral and peripheral physiologic functions of serotonin. Ligandactivity at 5-HT_(1B) is generally not associated with hallucination,although many hallucinogenic compounds are known to modulate 5-HT_(1A)receptors to impart physiological responses (Inserra et al., 2020,Pharmacol. Rev. 73: 202). 5-HT_(1B) receptors are implicated in variousbrain neurological disorders, including depression (Curr. Pharm. Des.2018, 24:2541-2548).

The term “5-HT_(2A) receptor”, as used herein, refers to a subclass of afamily of receptors for the neurotransmitter and peripheral signalmediator serotonin. 5-HT_(2A) receptors can mediate a plurality ofcentral and peripheral physiologic functions of serotonin. Centralnervous system effects can include mediation of hallucinogenic effectsof hallucinogenic compounds. 5-HT_(2A) receptors are implicated invarious brain neurological disorders (Nat. Rev. Drug Discov. 2022,21:463-473; Science 2022, 375:403-411).

The term “5-HT_(2B) receptor”, as used herein, refers to a subclass of afamily of receptors for the neurotransmitter and peripheral signalmediator serotonin. 5-HT_(2B) receptors can mediate a plurality ofcentral and peripheral physiologic functions of serotonin. Centralnervous system effects can include mediation of hallucinogenic effectsof hallucinogenic compounds. 5-HT_(bA) receptors are implicated invarious brain neurological disorders, including schizophrenia(Pharmacol. Ther. 2018, 181:143-155) and migraine (Cephalalgia 2017,37:365-371).

The term “5-HT_(3A) receptor”, as used herein, refers to a subclass of afamily of receptors for the neurotransmitter and peripheral signalmediator serotonin. 5-HT_(3A) receptors can mediate a plurality ofcentral and peripheral physiologic functions of serotonin. 5-HT_(3A)receptors are implicated in various brain neurological disorders,including depression (Expert Rev. Neurother. 2016, 16:483-95).

The term “ADRA1A receptor”, as used herein, refers to a subclass of afamily of receptors, also known as α1-adrenergic receptors, which can bemodulated by selective serotonin reuptake inhibitors (SSRIs) andtricyclic antidepressant (TCA) (Int. J. Mol Sci. 2021, 22: 4817; BrainRes. 1285 2009, 148-157). ADRA1A receptors are implicated in variousbrain neurological disorders, including depression.

The term “ADRA2A receptor”, as used herein, refers to a subclass of afamily of receptors, also known as a2-adrenergic receptors. ADRA2Areceptors are implicated in various brain neurological disorders,including Attention Deficit Hyperactivity Disorder (ADHD) (J. Am. Acad.Child. Adolesc. Psychiatry 2014, 53:153-73), mania, bipolar disorder,and schizophrenia.

The term “CHRM1 receptor”, as used herein, refers to a subclass ofreceptors also known as “cholinergic receptor muscarinic 1”, which canbe modulated by selective serotonin reuptake inhibitors (SSRIs) (e.g.,paroxetine) and tricyclic antidepressant (TCA). The class of CHRMreceptors are implicated in various brain neurological disorders,including depression, major depression disorder (MDD), and bipolardisorder (Mol. Psychiatry 2019, 24: 694-709).

The term “CHRM2 receptor”, as used herein, refers to a subclass ofreceptors also known as “cholinergic receptor muscarinic 2”, which canbe modulated by tricyclic antidepressant (TCA). The class of CHRMreceptors are implicated in various brain neurological disorders,including depression, major depression disorder (MDD), and bipolardisorder (Mol. Psychiatry 2019, 24: 694-709).

The term “CNR1 receptor”, as used herein, refers to a subclass ofreceptors also known as “cannabinoid receptor CB₁”, which can bemodulated by cannabinoid compounds. CNR receptors are implicated invarious brain neurological disorders, including depression andschizophrenia (Pharmacol. Res. 2021, 170: 105729).

The term “DRD1 receptor”, as used herein, refers to a subclass ofreceptors also known as “dopamine receptor D₁”, which can be modulatedby dopamine. Dopamine receptors are implicated in various brainneurological disorders, including schizophrenia, psychosis, anddepression (Neurosci. Lett. 2019, 691:26-34).

The term “DRD2S receptor”, as used herein, refers to a subclass ofreceptors also known as “dopamine receptor D₂S”, which can be modulatedby dopamine. Dopamine receptors are implicated in various brainneurological disorders, including schizophrenia, psychosis, anddepression (Neurosci. Lett. 2019, 691:26-34).

The term “OPRD1 receptor”, as used herein, refers to a subclass ofreceptors also known as “opioid receptor D₁”, which can be modulated byopioid compounds. OPRD1 receptors are implicated in various brainneurological disorders, including psychopathy, and substance abuseddisorder (Mol. Psychiatry 2020, 25:3432-3441).

The term “MAO-A”, as used herein, refers to an enzyme involved insignaling also known as “Monoamine oxygenase A”, which can catalyzereactions which modulate signaling molecules, notably, for example, thedeamination of the signaling molecules dopamine, norepinephrine, andserotonin. Compounds capable of modulating MOA, e.g., inhibitors of MOA,may be used to treat various brain neurological disorders, includingpanic disorders, depression, and Parkinson's disease (J. Clin.Psychiatry 2012, 73 Suppl. 1:37-41).

The term “DAT”, as used herein, refers to a transmembrane transportprotein also known as “dopamine active transporter”, which is involvedof transporting dopamine into the cytosol. DAT is implicated in variousbrain neurological disorders, notably dopamine related disorders such asattention deficit hyperactivity disorder (ADHD), bipolar disorder, andclinical depression, anxiety (Am. J. Med. Genet. B Neuropsychiatr.Genet. 2018, 177:211-231).

The term “NET”, as used herein, refers to a transmembrane transportprotein also known as “norepinephrine transporter” or “noradrenalinetransporter” or “NAT” which is involved in Na⁺/Cl⁻ dependent re-uptakeof extracellular norepinephrine or noradrenaline. NET is implicated invarious brain neurological disorders, including attention deficithyperactivity disorder (ADHD) and clinical depression (Neurosci.Biobehav. Rev, 2013, 37:1786-800).

The term “SERT”, as used herein, refers to a transmembrane transportprotein also known as “serotonin transporter” which is involved inneuronal serotonin transport, notably from the synaptic cleft back tothe presynaptic neuron, thereby terminating the action of serotonin.SERT is implicated in various brain neurological disorders, includinganxiety and depression (Pharmacol. Rep. 2018, 70:37-46).

The term “modulating receptors”, as used herein, refers to the abilityof a compound disclosed herein to alter the function of receptors. Areceptor modulator may activate the activity of a receptor, or inhibitthe activity of a receptor depending on the concentration of thecompound exposed to the receptor. Such activation or inhibition may becontingent on the occurrence of a specific event, such as activation ofa signal transduction pathway, and/or maybe manifest only in particularcell types. The term “modulating receptors,” also refers to altering thefunction of a receptor by increasing or decreasing the probability thata complex forms between a receptor and a natural binding partner to forma multimer. A receptor modulator may increase the probability that sucha complex forms between the receptor and the natural binding partner,may increase or decrease the probability that a complex forms betweenthe receptor and the natural binding partner depending on theconcentration of the compound exposed to the receptor, and or maydecrease the probability that a complex forms between the receptor andthe natural binding partner. It is further noted that the C₄-carboxylicacid-substituted tryptamine derivatives of the present disclosure mayalter the function of a receptor by acting as an agonist or antagonistof the receptor, and that C₄-carboxylic acid-substituted tryptaminederivatives according to the present disclosure may alter the functionof a receptor by directly interacting therewith or binding thereto, orby indirectly interacting therewith through one or more other molecularentities. In general, the receptor may be any receptor, including anyreceptor set forth herein, such as any of a 5-HT_(1A), 5-HT_(1B),5-HT_(2A), a 5-HT_(2B), 5-HT_(3A), ADRA1A, ADRA2A, CHRM1, CHRM2, CNR1,DRD1, DRD2S, or OPRD1 receptor, for example. Accordingly, it will beclear, that in order to refer modulating specific receptors, terms suchas “modulating 5-HT_(1A) receptors”, “modulating 5-HT_(1B) receptors”,“modulating 5-HT_(2A) receptors”, “modulating 5-HT_(2B) receptors”, andso forth, may be used herein.

The term “receptor-mediated disorder”, as used herein, refers to adisorder that is characterized by abnormal receptor activity. Areceptor-mediated disorder may be completely or partially mediated bymodulating a receptor. In particular, a receptor-mediated disorder isone in which modulation of the receptor results in some effect on anunderlying disorder e.g., administration of a receptor modulator resultsin some improvement in at least some of the subjects being treated. Ingeneral, the receptor may be any receptor, including any receptor setforth herein, such as any of a 5-HT_(1A), 5-HT_(1B), 5-HT_(2A), a5-HT_(2B), 5-HT_(3A), ADRA1A, ADRA2A, CHRM1, CHRM2, CNR1, DRD1, DRD2S,or OPRD1 receptor, for example. Accordingly, it will be clear, that inorder to refer specific receptor-mediated disorders, terms such as“5-HT_(1A) receptor-mediated disorder”, “5-HT_(1B) receptor-mediateddisorder”, “5-HT_(2A) receptor-mediated disorder”, “5-HT_(2B)receptor-mediated disorder”, and so forth, may be used.

The term “pharmaceutical formulation”, as used herein, refers to apreparation in a form which allows an active ingredient, including apsychoactive ingredient, contained therein to provide effectivetreatment, and which does not contain any other ingredients which causeexcessive toxicity, an allergic response, irritation, or other adverseresponse commensurate with a reasonable risk/benefit ratio. Thepharmaceutical formulation may contain other pharmaceutical ingredientssuch as excipients, carriers, diluents, or auxiliary agents.

The term “recreational drug formulation”, as used herein, refers to apreparation in a form which allows a psychoactive ingredient containedtherein to be effective for administration as a recreational drug, andwhich does not contain any other ingredients which cause excessivetoxicity, an allergic response, irritation, or other adverse responsecommensurate with a reasonable risk/benefit ratio. The recreational drugformulation may contain other ingredients such as excipients, carriers,diluents, or auxiliary agents.

The term “effective for administration as a recreational drug”, as usedherein, refers to a preparation in a form which allows a subject tovoluntarily induce a psychoactive effect for non-medical purposes uponadministration, generally in the form of self-administration. The effectmay include an altered state of consciousness, satisfaction, pleasure,euphoria, perceptual distortion, or hallucination.

The term “effective amount”, as used herein, refers to an amount of anactive agent, pharmaceutical formulation, or recreational drugformulation, sufficient to induce a desired biological or therapeuticeffect, including a prophylactic effect, and further including apsychoactive effect. Such effect can include an effect with respect tothe signs, symptoms or causes of a disorder, or disease or any otherdesired alteration of a biological system. The effective amount can varydepending, for example, on the health condition, injury stage, disorderstage, or disease stage, weight, or sex of a subject being treated,timing of the administration, manner of the administration, age of thesubject, and the like, all of which can be determined by those of skillin the art.

The terms “treating” and “treatment”, and the like, as used herein, areintended to mean obtaining a desirable physiological, pharmacological,or biological effect, and includes prophylactic and therapeutictreatment. The effect may result in the inhibition, attenuation,amelioration, or reversal of a sign, symptom or cause of a disorder, ordisease, attributable to the disorder, or disease, which includes mentaland psychiatric diseases and disorders. Clinical evidence of theprevention or treatment may vary with the disorder, or disease, thesubject, and the selected treatment.

The term “pharmaceutically acceptable”, as used herein, refers tomaterials, including excipients, carriers, diluents, or auxiliaryagents, that are compatible with other materials in a pharmaceutical orrecreational drug formulation and within the scope of reasonable medicaljudgement suitable for use in contact with a subject without excessivetoxicity, allergic response, irritation, or other adverse responsecommensurate with a reasonable risk/benefit ratio.

The terms “substantially pure” and “isolated”, as may be usedinterchangeably herein describe a compound, e.g., a C₄-carboxylicacid-substituted tryptamine derivative, which has been separated fromcomponents that naturally or synthetically accompany it. Typically, acompound is substantially pure when at least 60%, more preferably atleast 75%, more preferably at least 90%, 95%, 96%, 97%, or 98%, and mostpreferably at least 99% of the total material (by volume, by wet or dryweight, or by mole percent or mole fraction) in a sample is the compoundof interest. Purity can be measured by any appropriate method, e.g., bychromatography, gel electrophoresis or HPLC analysis.

General Implementation

As hereinbefore mentioned, the present disclosure relates to tryptaminederivatives. In particular, the present disclosure provides novelC₄-substituted tryptamine derivatives, and in particular toC₄-carboxylic acid-substituted tryptamine derivatives. In general, theherein provided compositions exhibit functional properties which deviatefrom the functional properties of tryptamine. Thus, for example, theC₄-carboxylic acid-substituted tryptamine derivatives can exhibitpharmacological properties which deviate from tryptamine. Furthermore,the C₄-carboxylic acid-substituted tryptamine derivatives may exhibitphysico-chemical properties which differ from tryptamine. Thus, forexample, C₄-carboxylic add-substituted tryptamine derivatives mayexhibit superior solubility in a solvent, for example, an aqueoussolvent. Furthermore, the C₄-carboxylic acid-substituted tryptaminederivatives may exhibit pharmacokinetics or pharmacodynamics which aredifferent from a non-substituted compound. The C₄-carboxylicacid-substituted tryptamine derivatives in this respect are useful inthe formulation of pharmaceutical or recreational drug formulations.

In what follows selected embodiments are described with reference to thedrawings.

Accordingly, in one aspect, the present disclosure provides derivativesof a compound known as tryptamine of which the chemical structure isshown in FIG. 1 . The derivatives herein provided are, in particular,C₄-substituted tryptamine derivatives, i.e., derivatives, wherein the C₄atom is bonded to a substituent group, notably a carboxylic acid moietyor derivative thereof.

Thus, in one aspect, the present disclosure provides, in accordance withthe teachings herein, in at least one embodiment, a compound havingchemical formula (I):

-   -   wherein R₄ is a carboxylic acid moiety or derivative thereof;    -   wherein R_(3a) and R_(3b) are each independently a hydrogen        atom, an alkyl group, or an aryl group.

Thus, referring to the chemical compound having the formula (I), in anaspect hereof, R₄ can be a carboxylic acid moiety or derivative thereof,i.e., a carboxylic acid moiety or derivative which is bonded via itsavailable oxygen atom to the C₄ atom of the tryptamine compound.

In some embodiments, in an aspect, the carboxylic acid moiety orderivative thereof can have the chemical formula (II):

wherein R_(4a) is an aryl group, a substituted aryl group, a heteroarylgroup, a substituted heteroaryl group, an alkyl group, a substitutedalkyl group, an amine group, or a substituted amine group.

In some embodiments, the aryl group and substituted aryl group can be aphenyl group and a substituted phenyl group, respectively.

In some embodiments, the substituted aryl group can be ahalo-substituted phenyl group.

In some embodiments, the alkyl group can be a C₁-C₁₀ alkyl group, inwhich optionally, at least one carbon atom in the alkyl chain isreplaced with an oxygen (O) atom. For example, in a C₆ alkyl group twocarbon atoms may be replaced with an O, or in a C₉ or C₈ alkyl chainthree carbon atoms may be replaced with an O.

In some embodiments, the substituted alkyl group can be a C₁-C₁₀ alkylgroup, wherein the optional substituents are at least one of halo, C₃-C₆cycloalkyl, or amino (NH₂).

In some embodiments, the substituted alkyl group can be a C₁-C₁₀ alkylgroup, wherein the optional substituent is a C₃-C₆ cycloalkane. TheC₃-C₆ cycloalkane can be terminally attached to the C₁-C₁₀ alkyl group.

In some embodiments, the substituted alkyl group can be a C₁-C₁₀ alkylgroup, wherein the optional substituent is cyclo-propane(C₃-cycloalkane). The cyclopropane can be terminally attached to theC₁-C₁₀ alkyl group.

In some embodiments, the substituted alkyl group can be a methyl groupsubstituted by a cyclopropane group. In some embodiments, thesubstituted alkyl group can be a methyl group substituted by acyclopropane group and an amino group.

In some embodiments, the aryl group can be a phenyl group in which twosubstituents on the phenyl group are joined together to form anadditional 5-7-membered carbocyclic or heterocyclic ring.

In some embodiments, the 5-7-membered ring can be a methylene-dioxyring, an ethylene-dioxy ring, or a dihydrofuryl ring.

In some embodiments, the substituted aryl group can be an optionallysubstituted phenyl group which is substituted with an acetamidyl groupor an alkoxycarbonyl group, such as methoxycarbonyl (CH₃OC(═O)—), or asubstituted carboxy group (—C(═O)O—R), including a carboxy groupsubstituted with an indole group (R) or substituted indole group (R),wherein the substituted indole group can be substituted with aC₃-ethylamine or a C₃-substituted ethylamine, for example, a C₃-alkylethylamine, e.g., a C₃-methyl-substituted amine, a C₃-ethyl-substitutedamine, or a C₃-propyl substituted amine.

In some embodiments, in an aspect, the substituted phenyl group can bean O-alkylated phenyl group.

In some embodiments, the substituted phenyl group can be an O-alkylatedphenyl group, in which the phenyl group can be substituted with one ormore O-alkyl groups.

In some embodiments, the O-alkyl group can be a methoxy group, an ethoxygroup, a propoxy group, an iso-propoxy group, or a butoxy group (n-but,s-but or t-but).

In some embodiments, the O-alkyl group can be a methoxy group, forexample, 1, 2, or 3 methoxy groups.

In some embodiments, the substituted phenyl group can be a halogenatedphenyl group.

In some embodiments, the substituted phenyl group can be aper-halogenated phenyl group, such as a perfluorinated phenyl group.

In some embodiments, the substituted phenyl group can be atrifluoromethylated phenyl group (—CF₃), or a trifluoromethoxy phenylgroup (—OCF₃).

In some embodiments, the substituted aryl group can be a substitutedphenyl group having one or more substituents which are independentlyselected from halo, alkoxy, alkyl, halo-substituted alkyl, orhalo-substituted alkoxy. Thus, for example, the substituted phenyl groupcan be substituted with a trifluoromethyl group (—CF₃) and a methoxygroup, or with a fluoro group and a methoxy group, or with a methylgroup and a fluoro group, or with a trifluoromethyl group (—CF₃) and atrifluoromethoxy group (—OCF₃), and so forth.

In some embodiments, the phenyl group can be substituted with one ormore of a trifluoromethoxy group (—OCF₃), a methoxy group or a halogenatom (fluoro, chloro, bromo, iodo).

In some embodiments, R_(4a) can be a substituted pyridine group.

In some embodiments, the substituted pyridine group can be anO-alkylated pyridine group, an O-arylated pyridine group or ahalogenated pyridine group (chloro, fluoro, bromo, or iodo).

In some embodiments, the O-alkyl group can be a one or more methoxygroups, for example one or two groups.

In some embodiments, the substituted pyridine group can be anO-alkylated pyridine group, an O-arylated pyridine group, or ahalogenated pyridine group.

In some embodiments, the O-alkylated pyridine group can be O-alkylatedby one or more methoxy groups.

In some embodiments, the O-alkylated pyridine group can be O-alkylatedby one or more methoxy groups and one or more halogen atoms (chloro,fluoro, bromo or iodo).

In some embodiments, the pyridine group can be substituted with a O-arylgroup.

In some embodiments, the O-aryl group can be an O-phenyl group.

In some embodiments, the substituted aryl group can be a substitutedphenyl group which is substituted by a carboxylate moiety.

In some embodiments, R_(4a) in formula (II) can be a substituted aminegroup wherein the substituent is —NH—CH₂R, where R is an organicradical. The organic radical can be any hydrocarbon radical, forexample, an alkyl radical, or substituted alkyl radical, e.g., a C₁-C₆alkyl radical, or a C₁-C₆ substituted alkyl radical, for example, aC₁-C₆ alkyl radical substituted with one or two amino groups orsubstituted amino groups, for example,R_(x)—NH—CH·-CH₂—CH₂—CH₂—NH—R_(y), wherein R_(x) and R_(y) can beindependently selected from —(C═O)—NH₂ and—(C═O)(C(CHCH₃CH₃)NH)(C═O)(NH)CH₂CH₂CH₂CH₃ (wherein the organic radicalis linked to be part of the amide substituent through the CH· carbonatom).

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(I):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(II):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(III):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(IV):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(V):

In some embodiments, in an aspect, in the compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(VI):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(VII):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(VIII):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(IX):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(X):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XI):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XII):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XIII):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XIV):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XV):

In some embodiments, in an aspect, in the compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XVI):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XVII):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XVIII):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XIX):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XX):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXI):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXII):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXIII):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXIV):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXV):

In some embodiments, in an aspect, in the compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXVI):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXVII): C(XXVII).

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXVIII):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXIX):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXX):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXXI):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXXII):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXXIII):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXXIV):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXXV):

In some embodiments, in an aspect, in the compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXXVI):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXXVII):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXXVIII):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XXXIX):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XL):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XLI):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XLII):

In an aspect, the present disclosure provides a compound having chemicalformula (I) wherein R₄ is a carboxylic acid moiety or derivativethereof, the compound having the chemical formula C(XLIII):

Referring further to the compound having chemical formula (I), R_(3a)and R_(3b) can be independently a hydrogen atom or a (C₁-C₂₀)-alkylgroup or an aryl group, for example a phenyl group. In anotherembodiment, R_(3a) and R_(3b) are independently a hydrogen atom or a(C₁-C₁₀)-alkyl group or an aryl group, for example a phenyl group. Inanother embodiment, R_(3a) and R_(3b) are independently a hydrogen atomor a (C₁-C₆)-alkyl group or an aryl group, for example a phenyl group.In another embodiment, R_(3a) and R_(3b) are independently a hydrogenatom, a methyl group, an ethyl group, or a propyl group, or an arylgroup, for example a phenyl group. Thus, for example, R_(3a) and R_(3b)can each be a methyl group, ethyl group or propyl group, or one ofR_(3a) and R_(3b) can be a methyl group, ethyl group or propyl group,and one of R_(3a) and R_(3b) can be a hydrogen atom, or one of R_(3a)and R_(3b) can be a phenyl group, and one of R_(3a) and R_(3b) can be ahydrogen atom.

Thus, to briefly recap, the present disclosure provides C₄-carboxylicacid-substituted tryptamine derivatives. The disclosure provides, inparticular, a chemical compound having a formula (I):

-   -   wherein R₄ is a carboxylic acid moiety or derivative thereof;        and    -   wherein R_(3a) and R_(3b) are each independently a hydrogen        atom, an alkyl group, or an aryl group. Example compounds, in        accordance with example embodiments, in his respect, include        each of compounds C(I), C(II), C(III), C(IV), C(V), C(VI),        C(VII), C(VIII), C(IX), C(X), C(XI), C(XII), C(XIII), C(XIV),        C(XV), C(XVI), C(XVII), C(XVIII), C(XIX), C(XX), C(XXI),        C(XXII), C(XXIII), C(XXIV), C(XXV), C(XXVI), C(XXVII),        C(XXVIII), C(XXIX), C(XXX), C(XXXI), C(XXXII), C(XXXIII),        C(XXXIV), C(XXXV), C(XXXVI), C(XXXVII), C(XXXVIII), C(XXXIX),        C(XL), C(XLI), C(XLII), and C(XLIII) set forth herein.

The C₄-carboxylic acid-substituted tryptamine derivatives of the presentdisclosure may be used to prepare a pharmaceutical or recreational drugformulation. Thus, in one embodiment, the present disclosure furtherprovides in another aspect, pharmaceutical and recreational drugformulations comprising C₄-carboxylic acid-substituted tryptaminederivatives. Accordingly, in one aspect, the present disclosure providesin a further embodiment a pharmaceutical or recreational drugformulation comprising a chemical compound having a formula (I):

-   -   wherein R₄ is a carboxylic acid moiety or derivative thereof;        and    -   wherein R_(3a) and R_(3b) are each independently a hydrogen        atom, an alkyl group, or an aryl group.

The pharmaceutical or recreational drug formulations may be prepared asliquids, tablets, capsules, microcapsules, nanocapsules, trans-dermalpatches, gels, foams, oils, aerosols, nanoparticulates, powders, creams,emulsions, micellar systems, films, sprays, ovules, infusions, teas,decoctions, suppositories, etc. and include a pharmaceuticallyacceptable salt or solvate of the C₄-substituted tryptamine derivativecompound together with an excipient. The term “excipient” as used hereinmeans any ingredient other than the chemical compound of the disclosure.In order to prepare a pharmaceutical drug formulation in accordanceherewith, the C₄-carboxylic acid-substituted tryptamine derivativecompounds are generally initially prepared and obtained in asubstantially pure form, most preferably, at least in a 98%, 99% or99.9% pure form, and thereafter formulated with a pharmaceuticallyacceptable excipient. As will readily be appreciated by those of skillin art, the selection of excipient may depend on factors such as theparticular mode of administration, the effect of the excipient onsolubility of the chemical compounds of the present disclosure andmethods for their preparation will be readily apparent to those skilledin the art. Such compositions and methods for their preparation may befound, for example, in “Remington's Pharmaceutical Sciences”, 22^(nd)Edition (Pharmaceutical Press and Philadelphia College of Pharmacy atthe University of the Sciences, 2012).

The dose when using the compounds of the present disclosure can varywithin wide limits, and as is customary and is known to those of skillin the art, the dose can be tailored to the individual conditions ineach individual case. The dose depends, for example, on the nature andseverity of the illness to be treated, on the condition of the patient,on the compound employed or on whether an acute or chronic disease stateis treated, or prophylaxis is conducted, on the mode of delivery of thecompound, or on whether further active compounds are administered inaddition to the compounds of the present disclosure. Representativedoses of the present invention include, but are not limited to, about0.001 mg to about 5000 mg, about 0.001 mg to about 2500 mg, about 0.001mg to about 1000 mg, about 0.001 mg to about 500 mg, about 0.001 mg toabout 250 mg, about 0.001 mg to about 100 mg, about 0.001 mg to about 50mg, and about 0.001 mg to about 25 mg. Representative doses of thepresent disclosure include, but are not limited to, about 0.0001 toabout 1,000 mg, about 10 to about 160 mg, about 10 mg, about 20 mg,about 40 mg, about 80 mg or about 160 mg. Multiple doses may beadministered during the day, especially when relatively large amountsare deemed to be needed, for example 2, 3 or 4, doses. Depending on thesubject and as deemed appropriate from the patient's physician or caregiver it may be necessary to deviate upward or downward from the dosesdescribed herein.

The pharmaceutical and drug formulations comprising the C₄-carboxylicacid-substituted tryptamine derivative compounds of the presentdisclosure may be administered orally. Oral administration may involveswallowing, so that the compound enters the gastrointestinal tract, orbuccal or sublingual administration may be employed by which thecompound enters the blood stream directly from the mouth. Formulationssuitable for oral administration include both solid and liquidformulations.

Solid formulations include tablets, capsules (containing particulates,liquids, microcapsules, or powders), lozenges (including liquid-filledlozenges), chews, multi- and nano-particulates, gels, solid solutions,liposomal preparations, microencapsulated preparations, creams, films,ovules, suppositories, and sprays.

Liquid formulations include suspensions, solutions, syrups, and elixirs.Such formulations may be employed as fillers in soft or hard capsulesand typically comprise a carrier, for example, water, ethanol,polyethylene glycol, propylene glycol, methylcellulose, or a suitableoil, and one or more emulsifying agents and/or suspending agents. Liquidformulations may also be prepared by the reconstitution of a solid, forexample, from a sachet.

Binders are generally used to impart cohesive qualities to a tabletformulation. Suitable binders include microcrystalline cellulose,gelatin, sugars, polyethylene glycol, natural and synthetic gums,polyvinylpyrrolidone, pregelatinized starch, hydroxypropyl cellulose andhydroxypropyl methylcellulose.

Tablets may also contain diluents, such as lactose (monohydrate,spray-dried monohydrate, anhydrous and the like), mannitol, xylitol,dextrose, sucrose, sorbitol, microcrystalline cellulose, starch, anddibasic calcium phosphate dihydrate.

Tablets may also optionally comprise surface active agents, such assodium lauryl sulfate and polysorbate 80. When present, surface activeagents may comprise from 0.2% (w/w) to 5% (w/w) of the tablet.

Tablets may further contain lubricants such as magnesium stearate,calcium stearate, zinc stearate, sodium stearyl fumarate, and mixturesof magnesium stearate with sodium lauryl sulphate. Lubricants generallycomprise from 0.25% (w/w) to 10% (w/w), from 0.5% (w/w) to 3% (w/w) ofthe tablet.

In addition to the C₄-carboxylic acid-substituted tryptamine derivativecompounds, tablets may contain a disintegrant. Examples of disintegrantsinclude sodium starch glycolate, sodium carboxymethyl cellulose, calciumcarboxymethyl cellulose, croscarmellose sodium, crospovidone,polyvinylpyrrolidone, methyl cellulose, microcrystalline cellulose,lower alkyl-substituted hydroxypropyl cellulose, starch, pregelatinizedstarch and sodium alginate. Generally, the disintegrant will comprisefrom 1% (w/w) to 25% (w/w) or from 5% (w/w) to 20% (w/w) of the dosageform.

Other possible auxiliary ingredients include anti-oxidants, colourants,flavouring agents, preservatives, and taste-masking agents.

For tablet dosage forms, depending on the desired effective amount ofthe chemical compound, the chemical compound of the present disclosuremay make up from 1% (w/w) to 80% (w/w) of the dosage form, moretypically from 5% (w/w) to 60% (w/w) of the dosage form.

Example tablets contain up to about 80% (w/w) of the chemical compound,from about 10% (w/w) to about 90% (w/w) binder, from about 0% (w/w) toabout 85% (w/w) diluent, from about 2% (w/w) to about 10% (w/w)disintegrant, and from about 0.25% (w/w) to about 10% (w/w) lubricant.

The formulation of tablets is discussed in “Pharmaceutical Dosage Forms:Tablets”, Vol. 1-Vol. 3, by CRC Press (2008).

The pharmaceutical and recreational drug formulations comprising theC₄-carboxylic acid-substituted tryptamine derivative compound of thepresent disclosure may also be administered directly into the bloodstream, into muscle, or into an internal organ. Thus, the pharmaceuticaland recreational drug formulations can be administered parenterally (forexample, by subcutaneous, intravenous, intraarterial, intrathecal,intraventricular, intracranial, intramuscular, or intraperitonealinjection). Parenteral formulations are typically aqueous solutionswhich may contain excipients such as salts, carbohydrates, and bufferingagents (in one embodiment, to a pH of from 3 to 9), but, for someapplications, they may be more suitably formulated as a sterilenon-aqueous solution or as a dried form to be used in conjunction with asuitable vehicle such as sterile water.

Formulations comprising the C₄-carboxylic acid-substituted tryptaminederivative compound of the present disclosure for parenteraladministration may be formulated to be immediate and/or modifiedrelease. Modified release formulations include delayed-, sustained-,pulsed-, controlled-, targeted and programmed release. Thus, thechemical compounds of the disclosure may be formulated as a solid,semi-solid, or thixotropic liquid for administration as an implanteddepot providing modified release of the active compound. Examples ofsuch formulations include drug-coated stents andpoly(dl-lactic-coglycolic)acid (PGLA) microspheres.

The pharmaceutical or recreational drug formulations of the presentdisclosure also may be administered topically to the skin or mucosa,i.e., dermally or transdermally. Example pharmaceutical and recreationaldrug formulations for this purpose include gels, hydrogels, lotions,solutions, creams, ointments, dusting powders, cosmetics, oils, eyedrops, dressings, foams, films, skin patches, wafers, implants, sponges,fibres, bandages and microemulsions. Liposomes may also be used. Examplecarriers include alcohol, water, mineral oil, liquid petrolatum, whitepetrolatum, glycerin, polyethylene glycol and propylene glycol.Penetration enhancers may be incorporate (see: for example, Finnin, B.and Morgan, T. M., 1999 J. Pharm. Sci, 88 (10), 955-958).

Other means of topical administration include delivery byelectroporation, iontophoresis, phonophoresis, sonophoresis andmicroneedle or needle-free (e.g., Powderject™, Bioject™, etc.)injection.

Pharmaceutical and recreational drug formulations for inhalation orinsufflation include solutions and suspensions in pharmaceuticallyacceptable, aqueous, or organic solvents, or mixtures thereof, andpowders. The liquid or solid pharmaceutical compositions can containsuitable pharmaceutically acceptable excipients. In some embodiments,the pharmaceutical compositions are administered by the oral or nasalrespiratory route for local or systemic effect. Pharmaceuticalcompositions in pharmaceutically acceptable solvents can be nebulized byuse of inert gases. Nebulized solutions can be inhaled directly from thenebulizing device, or the nebulizing device can be attached to a facemask tent, or intermittent positive pressure breathing machine.Solution, suspension, or powder pharmaceutical compositions can beadministered, e.g., orally, or nasally, from devices that deliver theformulation in an appropriate manner.

It is noted that in some embodiments, the chemical compounds in thepharmaceutical formulation may act as pro-drugs. Pro-drugs represent amodality to control drug bioavailability, control timing of drugrelease, and/or reduce negative side-effects. Similarly, formulation anddelivery considerations can achieve these outcomes. Thus, adjustment andoptimization of all three variables together (prodrug moiety,formulation, delivery system) can be an effective strategy in drugdevelopment. Examples of ‘targeting systems’ designed to specificallyreach cells within the brain, obtained by simultaneously leveragingpro-drug, nanoparticle. And nasal administration strategies aredescribed, for example by Botti et al., 2021 Pharmaceutics 13:1114).

In further embodiments, in which the C₄-carboxylic acid-substitutedtryptamine derivative compounds of present disclosure are used as arecreational drug, the compounds may be included in compositions such asa food or food product, a beverage, a food seasoning, a personal careproduct, such as a cosmetic, perfume or bath oil, or oils (both fortopical administration as massage oil, or to be burned or aerosolized).The chemical compounds of the present disclosure may also be included ina “vape” product, which may also include other drugs, such as nicotine,and flavorings.

Thus, it will be clear that the C₄-carboxylic acid-substitutedtryptamine derivative compounds may be used as a pharmaceutical orrecreational drug. Accordingly, in another aspect the present disclosureprovides, in at least one embodiment, a use of a chemical compoundhaving a formula (I):

-   -   wherein R₄ is a carboxylic add moiety or derivative thereof; and    -   wherein R_(3a) and R_(3b) are each independently a hydrogen        atom, an alkyl group, or an aryl group, as a pharmaceutical or        recreational drug

The pharmaceutical formulations comprising the chemical compounds of thepresent disclosure may be used to treat a subject, and to treat a brainneurological disorder in a subject. Accordingly, the present disclosureincludes in a further embodiment, a method for treating a brainneurological disorder, the method comprising administering to a subjectin need thereof a pharmaceutical formulation comprising a chemicalcompound having a formula (I):

-   -   wherein R₄ is a carboxylic acid moiety or derivative thereof;        and    -   wherein R_(3a) and R_(3b) are each independently a hydrogen        atom, an alkyl group, or an aryl group, wherein the        pharmaceutical formulation is administered in an effective        amount to treat the brain neurological disorder.

Brain neurological disorders include psychiatric disorders that may betreated include, for example, neurodevelopmental disorders such asintellectual disability, global development delay, communicationdisorders, autism spectrum disorder, and attention-deficit hyperactivitydisorder (ADHD); bipolar and related disorders, such as mania, anddepressive episodes; anxiety disorder, such as generalized anxietydisorder (GAD), agoraphobia, social anxiety disorder, specific phobias(natural events, medical, animal, situational, for example), panicdisorder, and separation anxiety disorder; stress disorders, such asacute stress disorder, adjustment disorders, post-traumatic stressdisorder (PTSD), and reactive attachment disorder; dissociativedisorders, such as dissociative amnesia, dissociative identity disorder,and depersonalization/derealization disorder; somatoform disorders, suchas somatic symptom disorders, illness anxiety disorder, conversiondisorder, and factitious disorder; eating disorders, such as anorexianervosa, bulimia nervosa, rumination disorder, pica, and binge-eatingdisorder; sleep disorders, such as narcolepsy, insomnia disorder,hypersomnolence, breathing-related sleep disorders, parasomnias, andrestless legs syndrome; disruptive disorders, such as kleptomania,pyromania, intermittent explosive disorder, conduct disorder, andoppositional defiant disorder; depressive disorders, such as disruptivemood dysregulation disorder, major depressive disorder (MDD), persistentdepressive disorder (dysthymia), premenstrual dysphoric disorder,substance/medication-induced depressive disorder, postpartum depression,and depressive disorder caused by another medical condition, forexample, psychiatric and existential distress within life-threateningcancer situations (ACS Pharmacol. Transl. Sci. 4: 553-562; J. Psychiatr.Res. 137: 273-282); substance-related disorders, such as alcohol-relateddisorders, cannabis related disorders, inhalant-use related disorders,stimulant use disorders, and tobacco use disorders; neurocognitivedisorders, such as delirium; schizophrenia; compulsive disorders, suchas obsessive compulsive disorders (OCD), body dysmorphic disorder,hoarding disorder, trichotillomania disorder, excoriation disorder,substance/medication induced obsessive-compulsive disorder, andobsessive-compulsive disorder related to another medical condition; andpersonality disorders, such as antisocial personality disorder, avoidantpersonality disorder, borderline personality disorder, dependentpersonality disorder, histrionic personality disorder, narcissisticpersonality disorder, obsessive-compulsive personality disorder,paranoid personality disorder, schizoid personality disorder, andschizotypal personality disorder. Brain neurological disorders furtherinclude headache disorders, including migraines, including, for example,aural migraine, non-aural migraine, menstrual migraine, chronicmigraine, vestibular migraine, abdominal migraine, hemiplegic migraine,and other headache disorders.

In an aspect, the compounds of the present disclosure may be used to becontacted with a receptor to thereby modulate the receptor. Suchcontacting includes bringing a compound of the present disclosure andreceptor together under in vitro conditions, for example, by introducingthe compounds in a sample containing a receptor, for example, a samplecontaining purified receptors, or a sample containing cells comprisingreceptors. In vitro conditions further include the conditions describedin Example 1 hereof. Contacting further includes bringing a compound ofthe present disclosure and receptor together under in vivo conditions.Such in vivo conditions include the administration to an animal or humansubject, for example, of a pharmaceutically effective amount of thecompound of the present disclosure, when the compound is formulatedtogether with a pharmaceutically active carrier, diluent, or excipient,as hereinbefore described, to thereby treat the subject. Upon havingcontacted the receptor, the compound may activate the receptor orinhibit the receptor.

In an aspect receptors with which the compounds of the presentdisclosure may be contacted include, for example, the 5-HT_(1A)receptor, the 5-HT_(2A) receptor, the 5-HT_(1B) receptor, the 5-HT_(2B)receptor, the 5-HT_(3A) receptor, the ADRA1A receptor, the ADRA2Areceptor, the CHRM1 receptor, the CHRM2 receptor, the CNR1 receptor, theDRD1 receptor, the DRD2S receptor, or the OPRD1 receptor.

Thus, in a further aspect, the condition that may be treated inaccordance herewith can be any receptor mediated disorder, including,for example, a 5-HT_(1A) receptor-mediated disorder, a 5-HT_(2A)receptor-mediated disorder, a 5-HT_(1B) receptor-mediated disorder, a5-HT_(2B) receptor-mediated disorder, a 5-HT_(3A) receptor-mediateddisorder, a ADRA1A receptor-mediated disorder, a ADRA2Areceptor-mediated disorder, a CHRM1 receptor-mediated disorder, a CHRM2receptor-mediated disorder, a CNR1 receptor-mediated disorder, a DRD1receptor-mediated disorder, a DRD2S receptor-mediated disorder, or aOPRD1 receptor-mediated disorder. Such disorders include, but are notlimited to schizophrenia, psychotic disorder, attention deficithyperactivity disorder, autism, and bipolar disorder.

In some embodiments, upon having contacted a receptor and a receptor,the compound may modulate the receptor. However at the same time otherreceptors may not be modulated. E.g., a compound may activate or inhibita first receptor, e.g., a 5-HT_(1A) receptor, however the compound mayat the same time not modulate a second receptor, e.g., a 5-HT_(2A)receptor, or upon having contacted a first 5-HT_(2A) receptor and asecond 5-HT_(1A) receptor, the compound may modulate the first 5-HT_(2A)receptor, e.g., activate or inhibit the 5-HT_(2A) receptor, however thecompound may at the same time not modulate the second 5-HT_(1A)receptor.

In one embodiment, in an aspect, upon administration the compounds ofthe present disclosure can interact with an enzyme or transmembranetransport protein in the subject to thereby modulate the enzyme ortransmembrane transport protein and exert a pharmacological effect. Suchcontacting includes bringing a compound of the present disclosure andenzyme or transmembrane transport protein together under in vitroconditions, for example, by introducing the compounds in a samplecontaining an enzyme or transmembrane transport protein, for example, asample containing a purified enzyme or transmembrane transport protein,or a sample containing cells comprising an enzyme or transmembranetransport protein. Contacting further includes bringing a compound ofthe present disclosure and an enzyme or transmembrane transport proteintogether under in vivo conditions. Such in vivo conditions include theadministration to an animal or human subject, for example, of apharmaceutically effective amount of the compound of the presentdisclosure, when the compound is formulated together with apharmaceutically active carrier, diluent, or excipient, as hereinbeforedescribed, to thereby treat the subject.

In one embodiment, in an aspect, the enzyme can be monoamine oxidase A(MOA-A),

In one embodiment, in an aspect, the transmembrane transport protein canbe a dopamine active transporter (DAT), a norephedrine transporter(NET), or a serotonin transporter (SERT) transmembrane transportprotein.

It is noted that in one embodiment, in an aspect, upon administrationthe compound having formula (I) may be in vivo hydrolyzed to form acompound having chemical formula (VI):

-   -   wherein R_(3a) and R_(3b) are each independently a hydrogen        atom, an alkyl group, or an aryl group,    -   and wherein the compound having chemical formula (VI) interacts        with a receptor to thereby modulate the receptor in the subject        and exert a pharmacological effect. In this respect, the        compounds of the present disclosure may be formulated as a        pro-drug pharmaceutical formulation, i.e., a formulation wherein        it is not the formulated compound itself that mediates a        pharmacological effect, but rather a compound that is obtained        following in vivo hydrolyzation of the formulated compound by        the subject. Hydrolyzation may occur, for example, in the        gastro-intestinal tract of a person upon oral delivery of a        pro-drug pharmaceutical formulation.

Turning now to methods of making the C₄-carboxylic acid-substitutedtryptamine derivative compounds of the present disclosure, it isinitially noted, by way of general comment that the C₄-carboxylicacid-substituted tryptamine derivative compounds of the presentdisclosure may be prepared in any suitable manner, including by anyorganic chemical synthesis methods, biosynthetic methods, or acombination thereof.

Examples of suitable chemical reactions that may be performed inaccordance herewith are depicted in FIGS. 3A (i), 3A (ii), 4A, 5A, 6A,7A, 8A, 9A and 10A, and are further additionally detailed hereinafter inthe Example section.

In general, as is known to those of skill in the art, in order toperform chemical synthetic reactions selected reactants are reactedunder reaction conditions which permit the reactants to chemically reactwith each other and form a product, i.e., the C₄-carboxylicacid-substituted tryptamine derivative compounds of the presentdisclosure. Such reactions conditions may be selected, adjusted, andoptimized as known by those of skill in the art. The reactions may beconducted in any suitable reaction vessel (e.g., a tube, bottle).Suitable solvents that may be used are polar solvents such as, forexample, dichloromethane, dichloroethane, toluene, and so calledparticipating solvents such as acetonitrile and diethyl ether. Suitabletemperatures may range from, for example, e.g., from about −78° C. toabout 60° C. Furthermore, catalysts, also known as promoters, may beincluded in the reaction such as iodonium dicollidine perchlorate(IDCP), any silver or mercury salts, trimethylsilyltrifluoromethanesulfonate (TMS-triflate, TMSOTf), ortrifluoromethanesulfonic acid (triflic acid, TfOH), N-iodosuccinimide,methyl triflate. Furthermore, reaction times may be varied. As willreadily be appreciated by those of skill in the art, the reactionconditions may be optimized, for example, by preparing several reactantpreparations and reacting these in separate reaction vessels underdifferent reaction conditions, for example, different temperatures,using different solvents etc., evaluating the obtained C₄-carboxylicacid-substituted tryptamine derivative compounds product, adjustingreaction conditions, and selecting a desired reaction condition.

In accordance with the foregoing, in aspect, disclosed herein aremethods of making a chemical compound having chemical formula (I):

-   -   wherein R₄ is a carboxylic acid moiety or a derivative thereof;        and    -   wherein R_(3a) and R_(3b) are each independently a hydrogen        atom, an alkyl group, or an aryl group, wherein the method        involves the performance of at least one chemical synthesis        reaction selected from the reactions depicted in FIG. 3A (i), 3A        (ii), 4A, 5A, 6A, 7A, 8A, 9A, or 10A.

Referring to FIGS. 3A (i) and 3A (ii), in one embodiment, the compoundhaving chemical formula (I) can be a compound having formula C(V):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 3A (i) or FIG. 3A (ii).

Referring next to FIG. 4A, in one embodiment, the compound havingchemical formula (I) can be a compound having formula C(VI):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 4A.

Referring next to FIG. 5A, in one embodiment, the compound havingchemical formula (I) can be a compound having formula C(VII):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 5A.

Referring next to FIG. 6A, one embodiment, the compound having chemicalformula (I) can be a compound having formula C(III):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 6A.

Referring next to FIG. 7A, in one embodiment, the compound havingchemical formula (I) can be a compound having formula C(XLIII):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 7A.

Referring next to FIG. 8A, in one embodiment, the compound havingchemical formula (I) can be a compound having formula C(I):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 8A.

Referring next to FIG. 9A, one embodiment, the compound having chemicalformula (I) can be a compound having formula C(XX):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 9A.

Referring next to FIG. 10A, in one embodiment, the compound havingchemical formula (I) can be a compound having formula C(IV):

and the at least one chemical synthesis reaction is the chemicalsynthesis reaction depicted in FIG. 10A.

In some embodiments, the chemical compounds may be isolate in pure orsubstantially pure form. Thus the compounds may be, for example, atleast 90%, 95%, 96%, 97%, or 98%, or at least 99% pure.

It will now be clear from the foregoing that novel C₄-carboxylicacid-substituted tryptamine derivatives are disclosed herein. TheC₄-carboxylic acid-substituted tryptamine derivatives may be formulatedfor use as a pharmaceutical drug or recreational drug. Exampleembodiments and implementations of the present disclosure are furtherillustrated by the following examples.

EXAMPLES Example 1—Synthesis and Analysis of a First C₄-CarboxylicAcid-Substituted Tryptamine Derivative

Two example syntheses methods for a first C₄-carboxylic acid-substitutedtryptamine derivative are described in this Example 1. A first methodafforded a final product at 9% yield, and was performed at a small scale(18 mg product) as follows. Referring to FIG. 3A (i), to a suspension ofcompound (1) (16 mg) in dry dichloromethane (DCM) (10 ml) was added 22μl of triethylamine dropwise and 4-methoxybenzoyl chloride (27 mg).Notably, the synthesis of psilocin (1) has been described previously(Shirota et al., J. Nat. Prod. 2003, 66:885-887; Kargbo et al., ACSOmega 2020, 5:16959-16966). After stirring for minutes at roomtemperature, the mixture turned to clear solution. The mixture wasstirred at room temperature for 1-2 hours and the reaction was monitoredby thin layer chromatography (TLC). The reaction was then quenched bydiluted aqueous HCl (0.5N) and extracted with DCM three times. Thecombined organic extracts were washed with water, brine. Then dried overanhydrous MgSO₄. After concentration using a rotary evaporator, themixture residue was applied to a silica column for chromatographicpurification, eluting with 5% methanol in DCM to afford compound (2) asan off-white solid (18.1 mg, 9% yield). 1H NMR (CDCl₃): δ 9.43 (1H, s,NH), 8.22 (2H, m, ArH), 7.35 (1H, dd, ArH), 7.15 (1H, t, ArH), 7.04 (2H,d, ArH), 6.91 (1H, m, ArH), 6.83 (1H, m, ArH), 3.92 (3, s, OCH3), 3.11(2H, m, CH2), 2.97 (2H, m, CH2), 2.37 (6H, d, NCH3). LCMS results: calmass for C₂₀H₂₃N₂O₃ [M+H]: 339.1703. found: 339.1700. Purity wasdetermined to be 95%. It is noted that compound (2) corresponds with thechemical compound having chemical formula: C(V):

A second method to synthesize a compound having chemical formula C(V)improved upon the first method, as the latter afforded 74% yield and wasperformed on a comparatively larger scale (250 mg product) as follows.Referring to FIG. 3A (ii), a solution of psilocin 1 (200 mg, 979 μmol)and triethylamine (274 μL, 1.96 mmol) in DCM (8.0 mL) was cooled down to0° C. To it was added 4-methoxybenzoyl chloride (192 mg, 1.12 mmol) inDCM (0.5 mL). The resulting mixture was warmed up to RT and stirred for2 hours. At this time, another portion of 4-methoxybenzoyl chloride (192mg, 1.12 mmol) in DCM (0.5 mL) was added, and the reaction was stirredat RT for another hour. Methanol (2 mL) was added to the reaction, andthe volatiles were removed in vacuo. The crude residue was directlypurified by flash chromatography (FC) on silica gel (12 g, MeOH/DCM0:100 to 20:80, 10 CV, product eluting at 11% methanol) to afford theproduct as a brown oil. TLC showed co-elution of p-methoxybenzoic acidwith the product. This isolated material was re-dissolved in DCM (50mL), and extracted with saturated aqueous NaHCO₃ (2×30 mL). The aqueouslayer was back-extracted with DCM (xl), washed with brine, dried overanhydrous Na₂SO₄, filtered and concentrated to afford the pure product 2as an off-white foamy solid (245 mg, 74%). MS-ESI: calculated m/z forC₂₀H₂₃N₂O₃ [M+H]⁺: 339.1703. found: 339.1700. ¹H NMR (400 MHz, CDCl₃) δ8.27-8.21 (m, 3H), 7.23 (dd, J=8.2, 1.0 Hz, 1H), 7.17 (t, J=7.8 Hz, 1H),7.03-6.98 (m, 2H), 6.95 (dd, J=2.3, 1.1 Hz, 1H), 6.88 (dd, J=7.6, 1.0Hz, 1H), 3.90 (s, 3H), 2.92-2.84 (m, 2H), 2.60-2.52 (m, 2H), 2.09 (s,6H). Purity was determined to be 95%. It is noted that compound (2)corresponds with the chemical compound having chemical formula C(V).

Assessment of Cell Viability Upon Treatment of a Psilocin Derivative.

To establish suitable ligand concentrations for competitive bindingassays, PrestoBlue assays were first performed. The PrestoBlue assaymeasures cell viable activity based on the metabolic reduction of theredox indicator resazurin, and is a preferred method for routine cellviability assays (Terrasso et al., 2017, J. Pharmacol. Toxicol. Methods83: 72). Results of these assays were conducted using both controlligands (e.g., psilocybin, psilocin, DMT, tryptophan) and novelderivatives, in part as a pre-screen for any remarkable toxic effects oncell cultures up to concentrations of 1 mM. A known cellular toxin(Triton X-100, Pyrgiotakis G. et al., 2009, Ann. Biomed. Eng. 37:1464-1473) was included as a general marker of toxicity. Drug-inducedchanges in cell health within simple in vitro systems such as the HepG2cell line are commonly adopted as first-line screening approaches in thepharmaceutical industry (Weaver et al., 2017, Expert Opin. Drug Metab.Toxicol. 13: 767). HepG2 is a human hepatoma that is most commonly usedin drug metabolism and hepatotoxicity studies (Donato et al., 2015,Methods Mol Biol 1250: 77). Herein, HepG2 cells were cultured usingstandard procedures using the manufacture's protocols (ATCC, HB-8065).Briefly, cells were cultured in Eagle's minimum essential mediumsupplemented with 10% fetal bovine serum and grown at 37° C. in thepresence of 5% CO₂. To test the various compounds with the cell line,cells were seeded in a clear 96-well culture plate at 20,000 cells perwell. After allowing cells to attach and grow for 24 hours, compoundswere added at 1 mM, 10 mM, 100 mM, and 1 mM. Methanol or DMSO were usedas vehicles, at concentrations 0, 0.001, 0.01, 0.1, and 1% (methanol) or0, 0.001, 0.01, 0.1, and 1% (DMSO), respectively. As a positive controlfor toxicity, TritonX concentrations used were 0.0001, 0.001, 0.01 and0.1%. Cells were incubated with compounds for 48 hours before assessingcell viability with the PrestoBlue assay following the manufacture'sprotocol (ThermoFisher Scientific, P50200). PrestoBlue reagent was addedto cells and allowed to incubate for 1 hour before reading. Absorbancereadings were performed at 570 nm with the reference at 600 nm on aSpectraMax iD3 plate reader. Non-treated cells were assigned 100%viability. Bar graphs show the mean+/−SD, n=3. Significance wasdetermined by 2-way ANOVA followed by Dunnett's multiple comparison testand is indicated by ** (P<0.0001), **(P<0.001), *(P<0.005). Dataacquired for the derivative having chemical formula (C-V) is displayedas “C-V” on the x-axes in FIG. 3B and FIG. 3C.

Radioligand Receptor Binding Assays.

Evaluation of drug binding is an essential step to characterization ofall drug-target interactions (Fang 2012, Exp. Opin. Drug Discov. 7:969).The binding affinity of a drug to a target is traditionally viewed as anacceptable surrogate of its in vivo efficacy (Núñez et al., 2012, DrugDisc Today 17: 10). Competition assays, also called displacement ormodulation binding assays, are a common approach to measure activity ofa ligand at a target receptor (Flanagan 2016, Methods Cell Biol 132:191). In these assays, standard radioligands acting either as agonistsor antagonists are ascribed to specific receptors. In the case of Gprotein-coupled receptor 5-HT_(2A), [³H]ketanserin is a well-establishedantagonist used routinely in competition assays to evaluate competitiveactivity of novel drug candidates at the 5-HT_(2A) receptor (Maguire etal., 2012, Methods Mol Biol 897: 31). Thus, to evaluate activity ofnovel C₄-substituted tryptamine derivatives at the 5-HT_(2A) receptor,competition assays using [³H]ketanserin were employed as follows. SPAbeads (RPNQ0010), [³H]ketanserin (NET1233025UC), membranes containing5-HT_(2A) (ES-313-M400UA), and isoplate-96 microplate (6005040) were allpurchased from PerkinElmer. Radioactive binding assays were carried outusing Scintillation Proximity Assay (SPA). For saturation bindingassays, mixtures of 10 ug of membrane containing 5-HT_(2A) receptor waspre-coupled to 1 mg of SPA beads at room temperature in a tube rotatorfor 1 hour in binding buffer (50 mM Tris-HCl pH7.4, 4 mM CaCl₂, 1 mMascorbic acid, 10 mM pargyline HCl). After pre-coupling, the beads andmembrane were aliquoted in an isoplate-96 microplate with increasingamounts of [³H]ketanserin (0.1525 nM to 5 nM) and incubated for twohours at room temperature in the dark with shaking. After incubation,the samples were read on a MicroBeta 2 Microplate Counter (PerkinElmer). Determination of non-specific binding was carried out in thepresence of 20 mM of spiperone (S7395-250MG, Sigma). Equilibrium bindingconstants for ketanserin (K_(d)) were determined from saturation bindingcurves using the ‘one-site saturation binding analysis’ method ofGraphPad PRISM software (Version 9.2.0). Competition binding assays wereperformed using fixed (1 nM) [³H]ketanserin and different concentrationsof tryptophan (3 nM to 1 mM), psilocin (30 μM to 10 mM) or unlabeledtest compound (3 nM to 1 mM) similar to the saturation binding assay.K_(i) values were calculated from the competition displacement datausing the competitive binding analysis from GraphPad PRISM software.Tryptophan was included as a negative control as it has no activity atthe 5-HT_(2A) receptor. In contrast, psilocin was used as a positivecontrol since it has established binding activity at the 5-HT_(2A)receptor (Kim et al., 2020, Cell 182: 1574). FIG. 3D depicts thesaturation binding curves for [³H]ketanserin at the 5-HT_(2A) receptor.Panel A shows the specific saturation ligand binding of [³H]ketanserin(from 0.1525 nM to 5 nM) to membranes containing 5-HT_(2A) receptor,which was obtained after subtracting non-specific binding values (shownin Panel B). Specific binding in counts per minute (cpm) was calculatedby subtracting non-specific binding from total binding. Specific binding(pmol/mg) was calculated from pmol of [³H]ketanserin bound per mg ofprotein in the assay. The K_(d) was calculated by fitting the data withthe one-site binding model of PRISM software (version 9.2.0). FIG. 3Eshows the competition binding curves for psilocin as a positive control(binding). This assay was conducted twice, yielding data shown in PanelsA and B, respectively. FIG. 3F shows the competition binding curves forpsilocybin (Panel A) and tryptophan (Panel B). Psilocybin is known torelease the 5-HT_(2A)-binding metabolite psilocin in vivo; however, theintact psilocybin molecule itself displays very weak (McKenna andPeroutka 1989, J Neurosci 9: 3482) or arguably negligible (PDSPCertified Data; https://pdsp.unc.edu/databases/pdsp.php) binding at5-HT_(2A). Tryptophan is included as a negative control (no binding).The competition binding curve for compound with formula C(V), designated“C-V” in FIG. 3G.

Cell Lines and Control Ligands Used to Assess Activity at 5-HT_(1A).

CHO-K1/Ga₁₅ (GenScript, M00257) (−5-HT_(1A)) and CHO-K1/5-HT_(1A)/Ga₁₅(GenScript, M00330) (+5-HT_(1A)) cells lines were used. Briefly,CHO-K1/Ga₁₅ is a control cell line that constitutively expresses Ga₁₅which is a promiscuous G_(q) protein. This control cell line lacks anytransgene encoding 5-HT_(1A) receptors, but still responds to forskolin;thus, cAMP response to forskolin should be the same regardless ofwhether or not 5-HT_(1A) agonists are present. Conversely,CHO-K1/5-HT_(1A)/Ga₁₅ cells stably express 5-HT_(1A) receptor in theCHO-K1 host background. Notably, Ga₁₅ is a promiscuous G protein knownto induce calcium flux response, present in both control and 5-HT_(1A)cell lines. In +5-HT_(1A) cells, Ga₁₅ may be recruited in place ofG_(ai/o), which could theoretically dampen cAMP response (Rojas andFiedler 2016, Front Cell Neurosci 10: 272). Thus, we included two known5-HT_(1A) agonists, DMT (Cameron and Olson 2018, ACS Chem Neurosci 9:2344) and serotonin (Rojas and Fiedler 2016, Front Cell Neurosci 10:272) as positive controls to ensure sufficient CAMP response wasobserved, thereby indicating measurable recruitment of G_(ai/o) proteinto activated 5-HT_(1A) receptors. In contrast, tryptophan is not knownto activate 5-HT_(1A) receptors, and was thus used as a negativecontrol. Cells were maintained in complete growth media as recommendedby supplier (GenScript) which is constituted as follows: Ham's F12Nutrient mix (HAM's F12, GIBCO #11765-047) with 10% fetal bovine serum(FBS) (Thermo Scientific #12483020), 200 mg/ml zeocin (Thermo Scientific#R25005) and/or 100 mg/ml hygromycin (Thermo Scientific #10687010). Thecells were cultured in a humidified incubator with 37° C. and 5% CO₂.Cells maintenance was carried out as recommended by the cell supplier.Briefly, vials with cells were removed from the liquid nitrogen andthawed quickly in 37° C. water bath. Just before the cells werecompletely thawed the vial's outside was decontaminated by 70% ethanolspray. The cell suspension was then retrieved from the vial and added towarm (37° C.) complete growth media, and centrifuged at 1,000 rpm for 5minutes. The supernatant was discarded, and the cell pellet was thenresuspended in another 10 ml of complete growth media, and added to the10 cm cell culture dish (Greiner Bio-One #664160). The media was changedevery third day until the cells were about 90% confluent. The ˜90%confluent cells were then split 10:1 for maintenance or used forexperiment.

Evaluation of 5-HT_(1A) Receptor Modulation.

As 5-HT_(1A) activation inhibits cAMP formation, the agonist activity oftest molecules on 5-HT_(1A) was measured via the reduction in the levelsof cAMP produced due to application of 4 mM forskolin. The change inintracellular cAMP levels due to the treatment of novel molecules wasmeasured using cAMP-Glo Assay kit (Promega #V1501). Briefly, +5-HT_(1A)cells were seeded on 1-6 columns and base −5-HT_(1A) cells were seededon columns 7-12 of the white walled clear bottom 96-well plate (Corning,#3903). Both cells were seeded at the density of 30,000 cells/well in100 ml complete growth media and cultured 24 hrs in humidified incubatorat 37° C. and 5% CO₂. On the experiment day, the media of cells wasreplaced with serum/antibiotic free culture media. Then the cells weretreated for 20 minutes with test molecules dissolved in induction medium(serum/antibiotic free culture media containing 4 mM forskolin, 500 mMIBMX (isobutyl-1-methylxanthine, Sigma-Aldrich, Cat. #17018) and 100 mM(RO 20-1724, Sigma-Aldrich, Cat. #B8279)). Forskolin induced cAMPformation whereas IBMX and RO 20-1724 inhibited the degradation of cAMP.The level of luminescence in cells incubated with induction medium(containing 4 mM forskolin) without test molecules was normalized torepresent 100% cAMP in this assay. PKA was added to the lysate, mixed,and subsequently the substrate of the PKA was added. PKA was activatedby cAMP, and the amount of ATP consumed due to PKA phosphorylationdirectly corresponded to cAMP levels in the lysate. Reduced ATP causedreduced conversion of luciferin to oxyluciferin, conferring diminishedluminescence as the result of 5-HT_(1A) activation. FIG. 3H showsincreasing levels of cAMP in cultured cells incubated with increasingconcentrations of forskolin independent of 5-HT_(1A) expression. FIG. 3Iillustrates no reduction in cellular cAMP levels in either cell culture(+5-HT_(1A) and −5-HT1A) stimulated with induction medium and treatedwith increasing doses of tryptophan, indicating a lack of 5-HT_(1A)activity by this molecule in +5-HT_(1A) cells. FIG. 3J illustratesreduction in cAMP levels in 5-HT_(1A) receptor expressing cells(+5-HT_(1A)) stimulated with 4 mM forskolin as levels of psilocinincrease, indicating 5-HT_(1A) receptor binding by psilocin in thesecells. Conversely, this trend of decreasing % cAMP levels withincreasing psilocin is not observed in cells lacking expression of5-HT_(1A) receptor. FIG. 3K illustrates reduction in cAMP levels in5-HT_(1A) receptor expressing cells stimulated with 4 mM forskolin aslevels of serotonin (5-HT) increase, indicating 5-HT_(1A) receptorbinding by serotonin (5-HT) in these cells. Conversely, this trend ofdecreasing % cAMP levels with increasing serotonin (5-HT) is notobserved in cells lacking expression of 5-HT_(1A) receptor. 5-HT_(1A)receptor binding evaluation for compound with formula C(V) (designatedsimply “C-V” along the x-axis) is shown in FIG. 3L. Comparison of dataacquired in +5-HT_(1A) cultures with those acquired in −5-HT_(1A)cultures suggests mild receptor modulation at higher ligandconcentrations.

In Vitro Metabolic Stability Assays Using Intestinal Fractions, LiverFractions, Serum Fractions, Alkaline Phosphatase Buffer, EsteraseBuffer, and Control Buffer.

A fundamental evaluation in drug development is the assessment ofabsorption, distribution, metabolism, excretion, and pharmacokinetics(ADME/PK) (Eddershaw et al., 2000, Drug Discovery Today 5(9): 409-414).The first ADME screen that a novel chemical entity is subjected to is anin vitro metabolic stability screen (Ackley et al., 2004, Methods inPharmacology and Toxicology Optimization in Drug Discovery (in vitromethods), Yan Z, Caldwell G. W. Eds; Humana Press Inc, New Jersey, pp.151-164). Drug stability upon exposure to human liver microsomes andliver S9 cellular fractions is a common in vitro assay to approximate invivo, liver-based drug metabolism (Richardson et al., 2016 DrugMetabolism Letters 10:83-90). First-pass metabolism is also oftenapproximated in vitro using intestinal microsome and cellular S9fractions (Hatley et al., 2017, Biopharmaceuticals & Drug Disposition,38(2):155-160). Further, it is well known that human serum, andparticularly circulating serum esterases can contribute to systemic drugmetabolism (Williams, F M 1987, Pharmacology and Therapeutics,34:99-109). Many pharmacological agents are classified as prodrugs, asthey undergo metabolic transformation in vivo upon administration torelease the active drug compound into the systemic compartment (ZawilskaJ B, et al. 2013, Pharmacological Reports, 65:1-14). Psilocybin, aserotonergic psychedelic agent, is well known prodrug that ismetabolized into the psychoactive product, psilocin (Dinis-Oliveira, R J2017, Drug Metabolism Reviews, 49(1):84-91). To evaluate the capacity oftest molecules to similarly serve as prodrugs of psilocin,time-dependent, metabolic stability assays using human AB serum, humanintestinal microsomes (HIM), human intestinal S9 fractions (HIS9), humanliver microsomes (HLM), human liver S9 fractions (HLS9), human alkalinephosphatase, and porcine esterase were performed. Assays in enzyme-freebuffer were also performed for control purposes, and for generalassessment of compound stability. Liquid chromatography coupled massspectrometry (LC-MS) was employed to track the conversion of the testmolecules into psilocin. All intestinal and liver fractions and NADPHRapidStart reagent was purchased from Sekisui/XenoTech. Human AB serumwas purchased from Sigma. For intestine and liver metabolism assays, 2.5μM candidate compounds were incubated in 400 μg/ml of each cellularfraction (HLM, HLS9, HIM, or HIS9) in 50 mM potassium phosphate buffer(pH 7.4) containing 3 mM MgCl2 and 1 mM EDTA supplemented with NADPHRapidStart at 37° C. Samples were taken at the start of the assay, andat every 20 minutes for 2 hours. Time-point samples were precipitatedwith 1:1 volume of acetonitrile to quench the reaction before 76centrifugation at 4000×g for 20 minutes. Supernatants were analyzed forthe presence of candidate prodrugs (parent molecule) and psilocin (thepredicted metabolite) using Orbitrap LC-MS (Thermo Scientific) usingpreviously described methods (Menéndez-Perdomo et al., 2021, J MassSpectrom, 56: e4683). The serum assays were carried out in 10% human ABserum in 50 mM potassium phosphate buffer (pH 7.4) containing 3 mM MgCl₂and 1 mM EDTA. Bovine alkaline phosphatase assays were carried out usingone unit of enzyme in 50 mM potassium phosphate buffer (pH 7.4)containing 3 mM MgCl₂ and 1 mM EDTA. Porcine esterase assays werecarried out using one unit of purified enzyme in 50 mM potassiumphosphate buffer (pH 7.4) containing 3 mM MgCl₂ in 1 mM EDTA. Assayconcentrations (μM) of both parent ‘prodrug’ molecule and psilocinmetabolite, as quantified through LC-MS using routine standard curveprocedures, were plotted as functions of assay time (minutes). Themetabolism rate (T_(1/2)) was determined from the metabolism curve plotusing the one phase decay feature of GraphPad PRISM software (Version9.2.0). The quantity of parent prodrug at time zero was set as 100%.

Positive controls were first tested to ensure that assays werefunctioning properly. Psilocybin is known to be metabolized to psilocinin the intestine and through alkaline phosphatase (Dinis-Oliveira, 2017Drug Metab Rev 49: 84-91) and thus served as a positive control for HIM,HIS9 and alkaline phosphatase assays. Procaine is known to bemetabolized to 4-amino benzoic acid in serum, liver, and throughesterase (Henrikus and Kampffmeyer, 1992, Xenobiotica 22: 1357-1366) andthus served as a positive control for AB serum, HLM and esterase assays.Verapamil is known to be metabolized into a variety of metabolites inliver (Hanada et al., 2008, Drug Metab Dispos 36: 2037-2042)(catabolites not examined in this study) and thus served as anadditional control for HLS9 and HLM assays.

FIGS. 3M (i)-3M (iii) illustrate results of ‘psilocin-release’ metabolicconversion assays using psilocybin as the parent prodrug control for HIM(Panel C), HIS9 (Panel D) and alkaline phosphatase (Panel E) assays. Forcontext, psilocybin was further submitted to negative control bufferassay (Panel A), AB serum (Panel B), HLM (Panel F), and HLS9 (Panel G)assays. Notably, these plots demonstrate psilocybin is stable in liverfractions with no conversion to psilocin. Further, the stability ofpsilocybin was confirmed in assay buffer, confirming that transformationof this molecule is due to enzymes within the cellular fractions ratherthan due to buffer components. Finally, these results demonstratepsilocybin is stable in serum with no conversion to psilocin. FIGS. 3N(i)-3N (ii) illustrate results of additional controls for assayverification: procaine and AB serum (Panel A); procaine and HLM (PanelB); verapamil and HLS9 (Panel C); procaine and esterase (Panel D);verapamil and HLM (Panel E). FIGS. 3O (i)-3O (iii) show the metabolicstability curves for compound with formula C(V), designated “C-V,” incontrol buffer (Panel A), AB serum (Panel B), HIM (Panel C), HLM (PanelD), HIS9 (Panel E), HLS9 (Panel F), alkaline phosphatase (Panel G), andesterase (Panel H).

In Vivo Evaluation of 5-HT_(2A) Receptor Agonism in Mice.

Drug-induced Head Twitch Response (HTR), a rapid, involuntary movementof the mouse's head with little or no involvement of the trunk, is anestablished in vivo model behavior used to measure neuronal 5-HT_(2A)receptor (5-HT2AR) activation by established and novel hallucinogeniccompounds (Canal and Morgan 2012, Drug Testing Analysis, 4:556-576).Indeed, HTR is widely utilized as a behavioral proxy in mice and rats topredict human hallucinogenic potential and can reliably differentiatebetween hallucinogenic and non-hallucinogenic 5-HT2AR agonists(Halberstadt and Geyer 2013, Psychopharmacology 227: 727-739;Gonzalez-Maeso et al., 2007, Neuron 53:439-452). To evaluate 5-HT2ARagonisms in vivo, HTR was measured in mice treated with a control andtest compounds over a fixed window of time post-administration. Allexperiments were approved by the University of Calgary Animal Care andUse Committee in accordance with Canadian Council on Animal Careguidelines. Briefly, 8-week old C57BL/6-Elite male and female mice wereobtained from Charles River. Prior to compound administration, all micewere group-housed, then single-housed on a 12:12 h light/dark schedule(lights on at 07:00 hours) with ad libitum access to food and water.Before any behavioral screening, mice were handled and exposed to thetesting chamber for at least 5 min each day for three successive daysand habituated to the experimental room 1 h before testing. The testingchamber was cleaned with a 70% ethanol solution between experiments.Control and test compounds, which were prepared at stock concentrationsof 100 mM in DMSO, were diluted in sterile saline solution (0.9% NaCl).The sterile saline solution without control or test compounds (i.e.,0.9% NaCl) was dosed with 100 mM DMSO to create equivalent ‘vehicle’solution. Prior to drug administration, mice were video monitored for 30minutes in a plexiglass testing chamber (25.5×12.5×12.5 cm [L×W×H]) toallow for acclimation to the testing environment and to examine pre-drugspontaneous HTRs. After 30 minutes, compounds were administered viaintraperitoneal (i.p.) injection at 1 mg/kg and mice were videomonitored for 30 minutes then returned to their home cage. HTR analysiswas conducted by an individual blinded to the subject treatment groupusing Behavioral Observation Research Interactive Software (BORIS,version 7, DOI: 10.1111/2041-210X.12584). Pre-drug behavior was examinedduring the 15-to-30-minute window prior to drug administration.Post-drug behavior was analyzed during the 15-to-30-minute windowfollowing drug administration. HTR associated with i.p. administrationof psilocybin or vehicle were included as positive or negative controlmeasures, respectively. Elevated incidences of HTR within the definedperiod of monitoring was observed in (1) psilocybin-treated mice, and(2) those treated with compound “C-V,” relative to control mice treatedwith i.p. injected vehicle. These results are illustrated in FIG. 3P,wherein vehicle is designated “veh,” psilocybin is designated “PCB,”compound with formula C(V) is designated “C-V,” pre-drug data isdesignated “pre-”, and post-drug data is designated “pro-.” Eachreplicate mouse is shown as a black dot along the corresponding verticalbars (N=2-6 per compound).

Mouse Pharmacokinetic (PK) Evaluation of Drug Metabolism to Psilocin.

Prodrugs are molecules with little or no pharmacological activity intheir own right but have a built in structural lability, whether bychance or by design, that permits bioconversion in vivo. Psilocybin wasrecognized as a natural prodrug of the active agent psilocin shortlyafter the identification and chemical synthesis of the former compoundin 1957 (Coppola et al., 2022 J Xenobiot 12: 41-52).

To further explore the potential of novel C₄-carboxylic acid-substitutedtryptamine derivatives for use as psilocin prodrugs, a mouse PK studywas performed. The aim of this study was to evaluate the time-dependent,in vivo conversion of novel derivative (“parent molecule”) to activepsilocin metabolite. Specifically, the study was conducted using both PO(per os, by mouth) and IV (intravenous) dosing. Briefly, the procedurewas as follows. For every compound (i.e., parent molecule), N=12 maleC57B116 mice were administered a single IV does (1 mg/kg) or a singleoral dose (1, 3, or 10 mg/kg), with N=3 mice per dose group. Serialblood sampling via tail snip was performed at 8 time points up to 24hours post-dosing. Samples were collected in K2EDTA tubes, plasma wasseparated, and all samples were frozen until bioanalysis for parentcompound and psilocin metabolite. Psilocybin was also assessed as aparent compound using this same protocol to establish a controlbenchmark PK profile. LC-MS/MS methodology was developed for (1) eachparent compound, and (2) psilocin metabolite, using a 6-8 pointcalibration curve in singlet (75% of standards within +/−25% accuracy(+/−25% LLOQ)). Sample processing and analysis included 96 plasma and 4dosing solutions per compound, with two calibration curves bracketingthe sample batch. Nominal analyte concentrations were calculated fordosing solutions based on the quantity of weighed analyte dissolved inexact volume of dosing solution. However, to account for any analyteinstability or other confounding factors, dosing solutions were sampledby LC-MS immediately prior to animal administration to obtain “measured”analyte quantity. Measured dose was considered the same as nominal dosewhen the formulation concentration was within 20% of nominalconcentration. However, if the measured dose was outside this window,this new “measured” dose was used in all calculations. Each mouse wasdesignated its own number (e.g., M01, M02 . . . ). Calculated valueswere as follows: T_(max) is the time at which maximum analyteconcentration was observed; C_(max) is the maximum observedconcentration; Apparent t_(1/2) is the apparent terminal half-life;AUC_(0-tlast) is the area under the “concentration versus time curve”from time zero to the time of the last measurable concentration;AUC_(0-inf) is the area under the “concentration versus time curve” fromtime zero to infinity; MRT_(0-inf) is the mean residence time from timezero to infinity; Vas is the steady-state volume of distribution; F (%)is bioavailability=(Dose^(iv)*AUC^(po))/(Dose^(po)*AUC^(iv))*100. Afurther detailed description of the methodoly that was used to performthe foregoing mouse PK study can be found at:https://intervivo.com/pk-safety-studies/#pk-bridge; accessed Jul. 19,2022.

Results for psilocybin PK following psilocybin administration are foundin Tables 1A-1B, and FIG. 3Q. Notably, psilocybin was only detectable ini.v. administered animals; conversely, it was not detectable in orallyadministered animals at any dose, suggesting a degree of instabilityand/or quick conversion to psilocin. Results for psilocin PK followingpsilocybin administration are found in Tables 2A-2B (1 mg/kg IV dose),Tables 3A-3B (1 mg/kg oral dose), Tables 4A-4B (3 mg/kg oral dose),Tables 5A, B (10 mg/kg oral dose), Table 6 (psilocin exposure) and FIG.3R.

TABLE 1A Plasma concentrations of psilocybin following 1 mg/kg i.v.administration of psilocybin. Experimental Plasma concentration (ng/mL)time (h) M01 M02 M03 Mean ± SD 0.0833 19.7 76.8 334 144 ± 167 0.25 3.328.95 27.2 13.2 ± 12.5 0.5 No Peak 2.35 6.21 4.28 (n = 2) 1 No Peak NoPeak 1.21 1.21 (n = 1) 2 No Peak No Peak No Peak n/a 4 No Peak No PeakNo Peak n/a 6 No Peak No Peak No Peak n/a 8 No Peak No Peak 2.54 n/a n/adenotes not applicable. Bolded value was considered an outlier and notincluded in calculations.

TABLE 1B Summary of plasma PK parameters for psilocybin following 1mg/kg i.v. administration of psilocybin. Parameter estimate for eachanimal Parameter M01 M02 M03 Mean ± SD t_(max) (h) 0.0833 0.0833 0.08330.0833 ± 0.00  C_(max) (ng/mL) 19.7 76.8 334 144 ± 167

TABLE 2A Plasma concentrations of psilocin following 1 mg/kg i.v.administration of psilocybin. Experimental Plasma concentration (ng/mL)time (h) M01 M02 M03 Mean ± SD 0.0833 76.5 106 124  102 ± 24.0 0.25 84.561.3 73.5 73.1 ± 11.6 0.5 43.6 43.5 62.4 49.8 ± 10.9 1 36.7 25.5 20.527.6 ± 8.30 2 5.16 26.9 3.16 11.7 ± 13.2 4 1.98 5.36 1.70 3.01 ± 2.04 64.33 2.01 0.810 2.38 ± 1.79 8 0.439 0.250 1.32 0.670 ± 0.571

TABLE 2B Summary of plasma PK parameters for psilocin, following 1 mg/kgi.v. administration of psilocybina. Parameter estimate for each animalParameter M01 M02 M03 Mean ± SD t_(max) (h) 0.250 0.0833 0.0833  0.139 ±0.0962 C_(max) (ng/mL) 84.5 106 124  105 ± 19.8 C_(max)/Dose^(a) 84.5106 124  105 ± 19.8 (kg * ng/mL/mg) Apparent t_(1/2) (h) nc^(b) 0.905 nc0.905 (n = 1) AUC_(0-tlast) (h * ng/mL) 84.5 109 75.5 89.8 ± 17.5AUC_(0-tlast)/Doseª 84.5 109 75.5 89.8 ± 17.5 (h * kg * ng/mL/mg)AUC_(0-inf) (h * ng/mL) n/a^(c) 110 n/a 110 (n = 1) MRT_(0-inf) (h) n/a 1.64 n/a 1.64 (n = 1) ^(a)Psilocybin dose was used. ^(b)nc denotes notcalculable as the terminal phase is not well defined. ^(c)n/a denotesnot applicable.

TABLE 3A Plasma concentrations of psilocin following 1.56 mg/kg oraladministration of psilocybin. Experimental Plasma concentration (ng/mL)time (h) M04 M05 M06 Mean ± SD 0.25 50.2 53.8 29.6 44.5 ± 13.1 0.5 40.552.5 57.2 50.1 ± 8.61 1 26.8 31.2 37.9 32.0 ± 5.59 2 11.3 7.04 7.50 8.61± 2.34 4 1.64 1.86 1.25  1.58 ± 0.309 6 0.445 1.05 0.611 0.702 ± 0.313 81.24 0.511 0.738 0.830 ± 0.373 24 BLQ BLQ BLQ n/a BLQ denotes below thelower limit of quantitation (0.2 ng/mL). n/a denotes not applicable.

TABLE 3B Summary of plasma PK parameters for psilocin, following 1.56mg/kg oral administration of psilocybina. Parameter estimate for eachanimal Parameter M04 M05 M06 Mean ± SD t_(max) (h) 0.250   0.250 0.5000.333 ± 0.144 C_(max) (ng/mL) 50.2 53.8 57.2 53.7 ± 3.50C_(max)/Dose^(a) 32.2 34.5 36.7 34.4 ± 2.24 (kg * ng/mL/mg) Apparentt_(1/2) (h) nc^(b)   2.15^(c) nc 2.15 (n = 1) AUC_(0-tlast) 65.6 68.866.9 67.1 ± 1.61 (h * ng/mL) AUC_(0-tlast)/Doseª 42.1 44.1 42.9 43.0 ±1.03 (h * kg * ng/mL/mg) AUC_(0-inf) (h * ng/mL) n/a^(d) 70.4 n/a 70.4(n = 1) MRT_(0-inf) (h) n/a   1.53 n/a 1.53 (n = 1) ^(a)Administereddose of psilocybin (1.56 mg/kg) was used. ^(b)nc denotes not calculableas the terminal phase is not well defined. ^(c)Apparent t_(1/2) estimatemay not be accurate; sampling interval during the terminal phase <2 ×t_(1/2). ^(d)n/a denotes not applicable.

TABLE 4A Plasma concentrations of psilocin following 3 mg/kg oraladministration of psilocybin. Experimental Plasma concentration (ng/mL)time (h) M07 M08 M09 Mean ± SD 0.25 52.6 53.0 41.5 49.0 ± 6.53 0.5 55.362.0 35.0 50.8 ± 14.1 1 23.2 35.5 36.2 31.6 ± 7.31 2 13.1 10.5 23.2 15.6± 6.71 4 2.28 1.93 3.16  2.46 ± 0.634 6 1.43 1.04 1.79  1.42 ± 0.375 80.734 0.368 0.493 0.532 ± 0.186 24 BLQ 0.111 0.402 0.257 (n = 2) BLQdenotes below the lower limit of quantitation (0.2 ng/ml). Value initalics is below the lower limit of quantitation (BLQ, 0.2 ng/mL) butwas included in calculations.

TABLE 4B Summary of plasma PK parameters for psilocin, following 3 mg/kgoral administration of psilocybina Parameter estimate for each animalParameter M07 M08 M09 Mean ± SD t_(max) (h) 0.500 0.500 0.250 0.417 ±0.144 C_(max) (ng/mL) 55.3 62.0 41.5 52.9 ± 10.5 C_(max)/Dose^(a) 18.420.7 13.8 17.6 ± 3.48 (kg * ng/mL/mg) Apparent t_(1/2) (h)^(b) 2.45 6.58nc^(c) 4.51 (n = 2) AUC_(0-tlast) (h * ng/mL) 74.3 83.0 95.8 84.4 ± 10.8AUC_(0-tlast)/Doseª 24.8 27.7 31.9 28.1 ± 3.61 (h * kg * ng/mL/mg)AUC_(0-inf) (h * ng/mL) 76.9 84.1 n/a^(d) 80.5 (n = 2) MRT_(0-inf) (h)1.84 2.24 n/a  2.04 (n = 2) ^(a)Psilocybin dose was used. ^(b)For M07,apparent t_(1/2) estimate may not be accurate; sampling interval duringthe terminal phase <2 × t_(1/2). ^(c)nc denotes not calculable as theterminal phase is not well defined. ^(d)n/a denotes not applicable.

TABLE 5A Plasma concentrations of psilocin following 10 mg/kg oraladministration of psilocybin. Experimental Plasma concentration (ng/ml)time (h) M10 M11 M12 Mean ± SD 0.25 238 234 202  225 ± 19.7 0.5 202 289156  216 ± 67.5 1 145 156 166  156 ± 10.5 2 53.9 54.7 66.6 58.4 ± 7.11 48.32 23.5 10.2 14.0 ± 8.28 6 3.51 16.8 10.3 10.2 ± 6.65 8 3.13 5.18 7.065.12 ± 1.97 24 0.258 0.201 0.186  0.215 ± 0.0380 BLQ denotes below thelower limit of quantitation (0.2 ng/ml). Value in italics is below thelower limit of quantitation (BLQ, 0.2 ng/ml) but was included incalculations.

TABLE 5B Summary of plasma PK parameters for psilocin following 10 mg/kgoral administration of psilocybina. Parameter estimate for each animalParameter M10 M11 M12 Mean ± SD t_(max) (h) 0.250 0.500 0.250 0.333 ±0.144 C_(max) (ng/mL) 238 289 202  243 ± 43.7 C_(max)/Doseª 23.8 28.920.2 24.3 ± 4.37 (kg * ng/ml/mg) Apparent t_(1/2) (h) 4.64 3.02 3.09 3.58 ± 0.920 AUC_(0-tlast) (h * ng/mL) 348 457 387  397 ± 55.5AUC_(0-tlast)/Dose^(a) 34.8 45.7 38.7 39.7 ± 5.55 (h * kg * ng/mL/mg)AUC_(0-inf) (h * ng/mL) 349 458 388  398 ± 55.1 MRT_(0-inf) (h) 2.142.44 2.60  2.39 ± 0.236 ^(a)Psilocybin dose was used.

TABLE 6 Summary of mean plasma exposure of psilocin as a function ofpsilocybin dose. Psilocybin dose 1 mg/ 1.56 mg/ 3 mg/ 10 mg/ Parameterkg i.v. kg p.o. kg p.o. kg p.o. C_(max)/Doseª  105 ± 19.8 34.4 ± 2.2417.6 ± 3.48 24.3 ± 4.37 (kg * ng/ml/mg) Apparent t_(1/2) (h) 0.905 (n= 1) 2.15 (n = 1) 4.51 (n = 2)  3.58 ± 0.920 AUC_(0-tlast)/Dose^(a) 89.8± 17.5 43.0 ± 1.03 28.1 ± 3.61 39.7 ± 5.55 (h * kg * ng/ml/mg)

Results for compound C(V) PK following CMV administration are found inTables 7A and 7B. Notably, compound CMV was only detectable in i.v.administered animals; conversely, it was not detectable in orallyadministered animals at any dose, suggesting a degree of instabilityand/or quick conversion to psilocin. Furthermore, C(V) was determined tobe unstable in plasma (see notes in Table 7A and 7B) thus renderingLC-MS-determined quantities inaccurate.

TABLE 7A Plasma concentrations of C(V) following 1 mg/kg i.v.administration of C(V). Experimental Plasma concentration (ng/ml)^(a)time (h) M13 M14 M15 Mean ± SD 0.0833 6.53 53.8 13.5 24.6 ± 25.5 0.250.834 BLQ BLQ 0.834 (n = 1) 0.5 BLQ No Peak No Peak n/a 1 No Peak NoPeak No Peak n/a 2 No Peak No Peak No Peak n/a 4 No Peak No Peak No Peakn/a 6 No Peak No Peak No Peak n/a 8 No Peak No Peak No Peak n/a ^(a)Afreshly spiked calibration curve was used for quantification C(V) is notstable in plasma; concentrations are not considered accurate. BLQdenotes below the lower limit of quantitation (0.5 ng/ml). n/a denotesnot applicable.

TABLE 7B Summary of plasma PK parameters for C(V) following 1 mg/kg i.v.administration of C(V). Parameter estimate for each animal Parameter^(a)M13 M14 M15 Mean ± SD t_(max) (h) 0.0833 0.0833 0.0833 0.0833 ± 0.00 C_(max) (ng/mL) 6.53 53.8 13.5 24.6 ± 25.5 ^(a)Due to C(V) instabilityin plasma, the PK parameter estimates are not considered accurate.

Results for psilocin PK following CMV administration are found in Tables8A-8B (1 mg/kg IV dose), Tables 9A-9B (1 mg/kg oral dose), Tables10A-10B (3 mg/kg oral dose), Tables 11A-11B (10 mg/kg oral dose), Table12 (comparative summary for IV data), Table 13 (comparative summary fororal data), Table 14A (psilocin exposure) and FIGS. 3S (i) and 3S (ii).

TABLE 8A Plasma concentrations of psilocin following 1 mg/kg i.v.administration of C(V). Experimental Plasma concentration (ng/ml) time(h) M13 M14 M15 Mean ± SD 0.0833 59.4 210 119  129 ± 75.8 0.25 34.7 24.439.5 32.9 ± 7.72 0.5 15.7 22.5 19.8 19.3 ± 3.42 1 5.27 8.27 6.72 6.75 ±1.50 2 1.57 1.74 1.26  1.52 ± 0.243 4 0.321 1.33 0.941 0.864 ± 0.509 60.197 0.470 1.91 0.859 ± 0.920 8 BLQ 0.241 0.102 0.172 (n = 2) BLQdenotes below the lower limit of quantitation (0.2 ng/ml). Value initalics is below the lower limit of quantitation (BLQ, 0.2 ng/ml) butwas included in calculations.

TABLE 8B Summary of plasma PK parameters for psilocin following 1 mg/kgi.v. administration of C(V)^(a). Parameter estimate for each animalParameter M13 M14 M15 Mean ± SD t_(max) (h) 0.0833 0.0833 0.0833 0.0833± 0.00  C_(max) (ng/ml) 59.4 210 119  129 ± 75.8 C_(max)/Dose^(a) 59.4210 119  129 ± 75.8 (kg * ng/ml/mg) Apparent t_(1/2) (h) 1.06 1.62 nc^(b)  1.34 (n = 2) AUC_(0-tlast) 26.0 45.7 39.7 37.1 ± 10.1 (h *ng/mL) AUC_(0-tlast)/Dose^(a) 26.0 45.7 39.7 37.1 ± 10.1 (h * kg * ng/mL/mg) AUC_(0-inf) (h * ng/ 26.4 46.2  n/a^(c)  36.3 (n = 2) mL)MRT_(0-inf) (h) 0.797 0.936 n/a 0.867 (n = 2) ^(a)C(V) dose was used.^(b)nc denotes not calculable as the terminal phase is not well defined.^(c)n/a denotes not applicable

TABLE 9A Plasma concentrations of psilocin following 1 mg/kg oraladministration of C(V). Experimental Plasma concentration (ng/ml) time(h) M16 M17 M18 Mean ± SD 0.25 7.58 8.33 10.2 8.70 ± 1.35 0.5 8.91 5.768.34 7.67 ± 1.68 1 4.03 3.32 4.74  4.03 ± 0.710 2 1.65 0.88 1.28  1.27 ±0.385 4 0.525 0.379 0.770 0.558 ± 0.198 6 0.154 0.147 0.144  0.148 ±0.00513 8 0.123 BLQ 0.225 0.174 (n = 2) 24 No Peak BLQ BLQ n/a BLQdenotes below the lower limit of quantitation (0.2 ng/ml). Values initalics are below the lower limit of quantitation (BLQ, 0.2 ng/ml) butwereincluded in calculations. n/a denotes not applicable.

TABLE 9B Summary of plasma PK parameters for psilocin following 1 mg/kgoral administration of C(V)^(a). Parameter estimate for each animalParameter M16 M17 M18 Mean ± SD t_(max) (h) 0.500 0.250 0.250 0.333 ±0.144 C_(max) (ng/ml) 8.91 8.33 10.2  9.15 ± 0.957 C_(max)/Dose^(a) 8.918.33 10.2  9.15 ± 0.957 (kg * ng/ml/mg) Apparent t_(1/2) (h) 1.54 1.55nc^(b) 1.54 (n = 2) AUC_(0-tlast) (h * ng/mL) 11.6 8.51 12.5 10.9 ± 2.10AUC_(0-tlast)/Dose^(a) 11.6 8.51 12.5 10.9 ± 2.10 (h * kg * ng/mL/mg)AUC_(0-inf) (h * ng/mL) 11.9 8.84 n/a^(c) 10.4 (n = 2) MRT_(0-inf) (h)1.70 1.53 n/a  1.62 (n = 2) ^(a)C(V) dose was used. ^(b)nc denotes notcalculable as the terminal phase is not well defined. ^(c)n/a denotesnot applicable.

TABLE 10A Plasma concentrations of psilocin following 3 mg/kg oraladministration of C(V). Experimental Plasma concentration (ng/ml) time(h) M19 M20 M21 Mean ± SD 0.25 26.1 21.7 34.2 27.3 ± 6.34 0.5 26.4 25.023.6 25.0 ± 1.40 1 15.5 17.2 14.5 15.7 ± 1.37 2 5.46 3.54 3.86 4.29 ±1.03 4 1.07 0.836 0.507 0.804 ± 0.283 6 0.634 0.446 0.374 0.485 ± 0.1348 0.359 0.116 0.203 0.226 ± 0.123 24 No Peak BLQ BLQ n/a BLQ denotesbelow the lower limit of quantitation (0.2 ng/ml). Value in italics isbelow the lower limit of quantitation (BLQ, 0.2 ng/ml) but was includedin calculations. n/a denotes not applicable.

TABLE 10B Summary of plasma PK parameters for psilocin following 3 mg/kgoral administration of C(V). Parameter estimate for each animalParameter M19 M20 M21 Mean ± SD t_(max) (h) 0.500 0.500 0.250 0.417 ±0.144 C_(max) (ng/ml) 26.4 25.0 34.2 28.5 ± 4.96 C_(max)/Dose^(a) 8.808.33 11.4 9.51 ± 1.65 (kg * ng/ml/mg) Apparent t_(1/2) (h)^(b) 2.54 1.403.03  2.32 ± 0.834 AUC_(0-tlast) (h * ng/mL) 37.7 33.1 33.5 34.8 ± 2.54AUC_(0-tlast)/Dose^(a) 12.6 11.0 11.2  11.6 ± 0.847 (h * kg * ng/mL/mg)AUC_(0-inf) (h * ng/mL) 39.0 33.3 34.4 35.6 ± 3.02 AUC_(0-inf)/Doseª13.0 11.1 11.5 11.9 ± 1.01 (h * kg * ng/ml/mg) MRT_(0-inf) (h) 1.78 1.341.44  1.52 ± 0.229 ^(a)C(V) dose was used. ^(b)For M19 and M21, apparentt_(1/2) estimate may not be accurate; sampling interval during theterminal phase <2 × t_(1/2).

TABLE 11A Plasma concentrations of psilocin following 10 mg/kg oraladministration of C(V). Experimental Plasma concentration (ng/mL) time(h) M22 M23 M24 Mean ± SD 0.25 42.1 76.7 103 73.9 ± 30.5 0.5 54.8 78.855.3 63.0 ± 13.7 1 36.1 42.0 26.5 34.9 ± 7.82 2 17.3 22.4 16.6 18.8 ±3.17 4 8.72 3.48 3.01 5.07 ± 3.17 6 4.06 7.23 2.29 4.53 ± 2.50 8 1.412.51 3.87 2.60 ± 1.23 24 BLQ BLQ No Peak n/a BLQ denotes below the lowerlimit of quantitation (0.2 ng/ml). n/a denotes not applicable.

TABLE 11B Summary of plasma PK parameters for psilocin following 10mg/kg oral administration of C(V)^(a). Parameter estimate for eachanimal Parameter M22 M23 M24 Mean ± SD t_(max) (h) 0.500 0.500 0.2500.417 ± 0.144 C_(max) (ng/ml) 54.8 78.8 103 78.9 ± 24.1 C_(max)/Dose^(a)5.48 7.88 10.3 7.89 ± 2.41 (kg * ng/ml/mg) Apparent t_(1/2) (h) 1.52nc^(b) nc 1.52 (n = 1) AUC_(0-tlast) 108 129 100 112 ± 15.2 (h * ng/mL)AUC_(0-tlast)/Doseª 10.8 12.9 10.0 11.2 ± 1.52 (h * kg * ng/mL/mg)AUC_(0-inf) (h * ng/mL) 111 n/a^(c) n/a  111 (n = 1) MRT_(0-inf) (h)2.32 n/a  n/a 2.32 (n = 1) ^(a)C(V) dose was used. ^(b)nc denotes notcalculable as the terminal phase is not well defined. ^(c)n/a denotesnot applicable.

TABLE 12 Comparative summary of psilocin pharmacokinetic (PK) parametersfollowing intravenous (IV) dosing of psilocybin or compound C(V).Parameter Psilocybin C(V) Prodrug nominal 1 1 dose (mg/kg) Prodrugmeasured 1 1 dose (mg/kg)^(a) t_(max) (h)  0.139 ± 0.0962 0.0833 ± 0.00 C_(max) (ng/ml)  105 ± 19.8  129 ± 75.8 C_(max)/Dose^(b) _(nominal)  105± 19.8  129 ± 75.8 (kg * ng/ml/mg) C_(max)/Dose^(b) _(measured)  105 ±19.8  129 ± 75.8 (kg * ng/ml/mg) Apparent t_(1/2) (h)  0.905 (n = 1)1.34 (n = 2) AUC_(0-tlast) (h * ng/mL) 89.8 ± 17.5 37.1 ± 10.1AUC_(0-tlast)/Dose^(b) _(nominal) 89.8 ± 17.5 37.1 ± 10.1 (h * kg *ng/mL/mg) AUC_(0-tlast)/Dose^(b) _(measured) 89.8 ± 17.5 37.1 ± 10.1(h * kg * ng/ml/mg) AUC_(0-inf) (h * ng/mL)  110 (n = 1)  36.3 (n = 2)MRT_(0-inf) (h) 1.64 (n = 1) 0.867 (n = 2) ^(a)Measured dose is the sameas nominal dose when the formulation concentration was within 20% ofnominal concentration ^(b)Prodrug dose was used

TABLE 13 Comparative summary of psilocin pharmacokinetic (PK) parametersfollowing oral (PO) dosing of psilocybin or compound C(V). ParameterPsilocybin C(V) Prodrug nominal dose 1 3 10 1 3 10 (mg/kg) Prodrugmeasured dose 1.56 3 10 1 3 10 (mg/kg)^(a) t_(max) (h) 0.333 ± 0.1440.417 ± 0.144 0.333 ± 0.144 0.333 ± 0.144 0.417 ± 0.144 0.417 ± 0.144C_(max) (ng/mL) 53.7 ± 3.50 52.9 ± 10.5  243 ± 43.7  9.15 ± 0.957 28.5 ±4.96 78.9 ± 24.1 C_(max)/Dose^(b) _(nominal) 1.56 17.6 ± 3.48 24.3 ±4.37 1 9.51 ± 1.65 7.89 ± 2.41 (kg * ng/mL/mg) C_(max)/Dose^(b)_(measured) 34.4 ± 2.24 17.6 ± 3.48 24.3 ± 4.37  9.15 ± 0.957 9.51 ±1.65 7.89 ± 2.41 (kg * ng/mL/mg) Apparent t_(1/2) (h) 2.15 4.51  3.58 ±0.920 1.54  2.32 ± 0.834 1.52 (n = 1) (n = 2) (n = 2) (n = 1)AUC_(0-tlast) (h * ng/mL) 67.1 ± 1.61 84.4 ± 10.8  397 ± 55.5 10.9 ±2.10 34.8 ± 2.54  112 ± 15.2 AUC_(0-tlast)/Dose^(b) _(nominal) 34.4 ±2.24 28.1 ± 3.61 39.7 ± 5.55  9.15 ± 0.957  11.6 ± 0.847 11.2 ± 1.52(h * kg * ng/mL/mg) AUC_(0-tlast)/Dose^(b) _(measured) 43.0 ± 1.03 28.1± 3.61 39.7 ± 5.55 10.9 ± 2.10  11.6 ± 0.847 11.2 ± 1.52 (h * kg *ng/mL/mg) AUC_(0-inf) (h * ng/mL) 70.4 80.5  398 ± 55.1 10.4 35.6 ± 3.02111 (n = 1) (n = 2) (n = 2) (n = 1) MRT_(0-inf) (h) 1.53 2.04  2.39 ±0.236 1.62  1.52 ± 0.229 2.32 (n = 1) (n = 2) (n = 2) (n = 1)^(a)Measured dose is the same as nominal dose when the formulationconcentration was within 20% of nominal concentration. ^(c) nc denotesnot calculable as % AUC extrapolated from tlast to infinity is >20%,thus estimate is not considered accurate. ^(d)n/a denotes notapplicable.

TABLE 14A Summary of mean plasma exposure of psilocin as a function ofC(V) dose. C(V) dose 1 mg/kg 1 mg/kg 3 mg/kg 10 mg/ Parameter i.v. p.o.p.o. kg p.o. C_(max)/Dose^(a)  129 ± 75.8 9.15 ± 0.957 9.51 ± 1.65  7.89± 2.41 (kg * ng/ ml/mg) Apparent 1.34 1.54 2.32 ± 0.834 1.52 t_(1/2) (h)(n = 2) (n = 2) (n = 1) AUC_(0-tlast)/Doseª 37.1 ± 10.1 10.9 ± 2.10 11.6 ± 0.847 11.2 ± 1.52 (h * kg * ng/ml/mg)

In Vitro Survey of Pharmacological Interaction Profiles at Receptors,Transporters and Enzymes Linked to Targeted Health Conditions.

To expand pharmacological profiling to include a broader range oftargets with known involvement in, or connection to, brain neurologicaldisorders, compound C(V) was evaluated with respect to receptorinteraction (https://www.eurofinsdiscoveryservices.com/). Specifically,the cell-based screening assay panel known as “SAFETYscan E/IC150 ELECT”was used to generate data regarding interaction of derivative moleculeswith 20 different proteins, including 12 GPCR receptors (ADRA1A, ADRA2A,AVPR1A, CHRM1, CHRM2, CNR1, DRD1, DRD2S, HTR1A (5-HT_(1A)), HTR1B(5-HTR_(1B)), HTR2B (5-HT_(2B)), OPRD1), 3 ion channels (GABAA, HTR3A(5-HT_(3A)), NMDAR), one enzyme (MAO-A), and 3 transporters (DAT, NET,SERT).

i. EFC-Based cAMP Secondary Messenger Assay.

Of the 12 GPCR proteins, 8 were assayed via a cAMP secondary messengerassay: ADRA2A, CHRM2, CNR1, DRD1, DRD2S, HTR1A, HTR1B, OPRD1. Briefly,employed a panel of cell lines stably expressing non-tagged GPCRproteins that endogenously signal through cAMP. These assays monitoredthe activation of a GPCR through G_(i) or G_(s) secondary messengersignaling in a homogenous, non-imaging assay format using a technologytermed EnzymeFragment Complementation (EFC). EFC uses β-galactosidase(β-gal) as the functional endpoint. The β-gal enzyme is split into twocomplementary portions: Enzyme Acceptor (EA) and Enzyme Donor (ED). Inthe assay, exogenously introduced ED fused to cAMP (ED-cAMP) competeswith endogenously generated cAMP for binding to an anti-cAMP-specificantibody. Active β-gal is formed by complementation of exogenous EA toany unbound ED-cAMP. Active enzyme can then convert a chemiluminescentsubstrate, generating an output signal detectable on a standardmicroplate reader.

These 8 cAMP-based assays were conducted in both agonist and antagonistmodes, either in G_(s) format (no forskolin) or in G_(i) format (in thepresence of EC₈₀ forskolin). For G_(s) and G_(i) agonist assays: cellmedia was aspirated from GPCR-containing cultures and replaced with 15μl 2:1HBSS/1-mM HEPES:cAMP XS+Ab reagent. Five microlitres of derivativecompound, prepared as a stock solution (also containing EC₈₀ forskolinin the case of G_(i) format) were added to the cells at final targetconcentrations and pre-incubated for 30 minutes. Final assay vehicleconcentration was 1%. After pre-incubation, assay signal was generatedthrough the addition of (1) 20 μL CAMP XS+ ED/CL lysis cocktail, and (2)20 μL cAMP XS+ EA reagent, allowing incubation periods of one and threehours, respectively. Antagonist assays were performed in the same manneras agonist assays, except pre-incubation entailed exposure to the testderivative (30 minutes) followed by exposure to an established agonistat EC₈₀ (“agonist challenge”, 30 minutes). In the case of antagonistassays of G_(i)-coupled GPCRs, EC₈₀ forskolin was included in assaybuffers.

In all 8 cAMP assays (agonist or antagonist mode), the resultingchemiluminescent signal was measured using a PerkinElmer Envision™instrument. Compound activity was analyzed using CBIS data analysissuite (ChemInnovation, CA). Percent activity (%) was calculatedaccording to standard procedures. For example: in G_(s) agonist modeassays, percentage activity was calculated using the following formula:% activity=100%×[mean RLU of test derivative−mean RLU of vehiclecontrol]/[mean RLU of control ligand −mean RLU of vehicle control]. ForG_(s) antagonist mode assays, percentage inhibition was calculated usingthe following formula: % inhibition=100%×[1−[mean RLU of testderivative−mean RLU of vehicle control]/[mean RLU of EC₈₀ control ligand−mean RLU of vehicle control]]. For G_(i) agonist mode assays,percentage activity was calculated using the following formula: %activity=100%×[1−[mean RLU of test derivative−mean RLU of controlligand]/[mean RLU of vehicle control−mean RLU of control ligand]]. ForG_(i) antagonist or negative allosteric mode assays, percentageinhibition was calculated using the following formula: %inhibition=100%×[mean RLU of test compound−mean RLU of EC₈₀ controlligand]/[mean RLU of forskolin positive control−mean RLU of EC₈₀control]. For primary screens, percent response was capped at 0% or 100%where calculated percent response returned a negative value or a valuegreater than 100, respectively. To assess assay performance andestablish positive control benchmarks, ligands listed in Table 14B wereevaluated alongside test derivatives. Results for EFC-based CAMPsecondary messenger assays on GPCRs using compound C(V) ligand orpositive controls are shown in Table 14C.

ii. Calcium Secondary Messenger Assay.

Of the 12 GPCR proteins, 4 were assayed via a calcium secondarymessenger assay: ADRA1A, AVPR1A, CHRM1, HTR2B. Briefly, the Calcium NoWashPLUS assay monitors GPCR activity via G_(q) secondary messengersignaling in a live cell, non-imaging assay format. Eurofins DiscoverXemployed proprietary cell lines stably expressing G_(q)-coupled GPCRproteins. Calcium mobilization was monitored using a calcium-sensitivedye loaded into cells. GPCR activation by a test or control compoundresulted in the release of calcium from intracellular stores and anincrease in dye fluorescence that is measured in real-time.

The four GPCR proteins assayed via calcium secondary messenger assaywere surveyed in both agonist and antagonist modes. Cell lines wereexpanded from freezer stocks according to standard procedures, seededinto microplates and incubated at 37° C. prior to testing. Assays wereperformed in 1× dye loading buffer consisting of 1× dye (DiscoverX,Calcium No WashPLUS kit, Catalog No. 90-0091), 1× Additive A and 2.5 mMprobenecid in HBSS/20 mM Hepes. Cells were loaded with dye prior totesting. Media was aspirated from cells and replaced with 25 μL dyeloading buffer, incubated for 45 minutes at 37° C. and then 20 minutesat room temperature. For agonist determination, cells were incubatedwith sample compound to induce response. After dye loading, cells wereremoved from the incubator and 25 μL of 2× compound in HBSS/20 mM Hepeswas added using a FLIPR Tetra (MDS). Compound agonist activity wasmeasured on a FLIPR Tetra. Calcium mobilization was monitored for 2minutes with a 5 second baseline read. For antagonist determination,cells were pre-incubated with sample compound followed by agonistchallenge at the EC₈₀ concentration. After dye loading, cells wereremoved from the incubator and 25 μL 2× sample compound was added. Cellswere incubated for 30 minutes at room temperature in the dark toequilibrate plate temperature. After incubation, antagonistdetermination was initiated with addition of 25 μL 1× derivativecompound with 3×EC₈₀ agonist using FLIPR. Compound antagonist activitywas measured on a FLIPR Tetra (MDS). Calcium mobilization was monitoredfor 2 minutes with a 5 second baseline read. In both agonist andantagonist modes, data analysis was initiated using FLIPR, where areaunder the curve was calculated for the entire two minute read. Compoundactivity was analyzed using CBIS data analysis suite (ChemInnovation,CA). For agonist mode assays, percentage activity was calculated usingthe following formula: % activity=100%×[mean RFU of test compound−meanRFU of vehicle control]/[mean RFU control ligand −mean RFU of vehiclecontrol]. For antagonist mode assays, percentage inhibition wascalculated using the following formula: % inhibition=100%×[1−[mean RFUof test compound−mean RFU of vehicle control]/[mean RFU of EC₈₀control−mean RFU of vehicle control]]. For primary screens, percentresponse was capped at 0% or 100%, where calculated percent responsereturned a negative value or a value greater than 100, respectively. Toassess assay performance and establish positive control benchmarks,ligands listed in Table 14B were evaluated alongside test derivatives.Results for EFC-based cAMP secondary messenger assays on GPCRs usingcompound C(V) ligand or positive controls are shown in Table 14C.

iii. Ion Channel Assays.

Both ‘blocker’ and ‘opener’ activities of putative ligands on threedistinct ion channels (GABAA, HTR3A, NMDAR) were surveyed. Briefly,Eurofins DiscoverX was employed in conjunction with the FLIPR MembranePotential Assay Kit (Molecular Devices) which utilizes a proprietaryfluorescent indicator dye in combination with a quencher to reflectreal-time membrane potential changes associated with ionchannelactivation and ion transporter proteins. Unlike traditional dyes such asDiBAC, the FLIPR Membrane Potential Assay Kit detects bidirectional ionfluxes so both variable and control conditions can be monitored within asingle experiment. Cell lines were expanded from freezer stocksaccording to standard procedures, seeded onto microplates, and incubatedat 37° C. Assays were performed in 1× Dye Loading Buffer consisting of1× Dye and 2.5 mM probenecid when applicable. Cells were loaded with dyeprior to testing and incubated for 30-60 minutes at 37° C. For agonist(‘Opener’) assays, cells were incubated with sample (i.e., containingderivative or control compound; Table 14B) to induce response asfollows. Dilution of sample stocks was performed to generate 2-5× sample(i.e., containing derivative or control compound) in assay buffer. Next,10-25 μL of 2-5× sample was added to cells and incubated at 37° C. orroom temperature for 30 minutes. Antagonist (‘Blocker’) assays wereperformed using the same procedure except that after dye loading, cellswere removed from the incubator and 10-25 μL 2-5× sample (i.e.,containing derivative or control compound) was added to cells in thepresence of EC₈₀ agonist. Cells were incubated for 30 minutes at roomtemperature in the dark to equilibrate plate temperature. Compoundactivity was measured on a FLIPR Tetra (Molecular Devices). Compoundactivity was analyzed using CBIS data analysis suite (ChemInnovation,CA). For agonist mode assays, percentage activity was calculated usingthe following formula: % activity=100%×[mean RLU of test derivative−meanRLU of vehicle control]/[mean control ligand −mean RLU of vehiclecontrol]. For antagonist mode, percentage inhibition was calculatedusing the following formula: % inhibition=100%×[1−[mean RLU of testderivative−mean RLU of vehicle control]/[mean RLU of EC₈₀ control−meanRLU of vehicle control]]. For primary screens, percent response wascapped at 0% or 100% where calculated percent response returned anegative value or a value greater than 100, respectively. To assessassay performance and establish positive control benchmarks, ligandslisted in Table 14B were evaluated alongside test derivatives. Resultsfor EFC-based cAMP secondary messenger assays on GPCRs using compoundC(V) ligand or positive controls are shown in Table 14C.

iv. Neurotransmitter Transporter Uptake Assays.

The Neurotransmitter Transporter Uptake Assay Kit from Molecular Deviceswas used to examine impact of test compounds on 3 distinct transporters(DAT, NET, SERT). This kit provided a homogeneous fluorescence-basedassay for the detection of dopamine, norepinephrine or serotonintransporter activity in cells expressing these transporters. The kitemployed a fluorescent substrate that mimics the biogenic amineneurotransmitters that are taken into the cell through the specifictransporters, resulting in increased intracellular fluorescenceintensity. Cell lines were expanded from freezer stocks according tostandard procedures, seeded into microplates and incubated at 37° C.prior to testing. Assays were performed in 1× Dye Loading Bufferconsisting of 1× Dye, and 2.5 mM probenecid as applicable. Next, cellswere loaded with dye and incubated for 30-60 minutes at 37° C. “Blocker”or antagonist format assays were performed, where cells werepre-incubated with sample (i.e., containing sample derivative orpositive control compound) as follows. Dilution of sample stocks (i.e.,containing sample derivative or positive control compound; Table 14B)was conducted to generate 2-5× sample in assay buffer. After dyeloading, cells were removed from the incubator and 10-25 μL 2-5× sample(i.e., containing sample derivative or positive control compound) wasadded to cells in the presence of EC₈₀ agonist as appropriate. Cellswere incubated for 30 minutes at room temperature in the dark toequilibrate plate temperature. Compound activity was measured on a FLIPRTetra (Molecular Devices), and activity was analyzed using CBIS dataanalysis suite (ChemInnovation, CA). For antagonist (‘Blocker’) mode,percentage inhibition was calculated using the following formula: %inhibition=100%×[1−[mean RLU of test sample−mean RLU of vehiclecontrol]/[mean RLU of EC₈₀ control−mean RLU of vehicle control]]. Forprimary screens, percent response was capped at 0% or 100% wherecalculated percent response returned a negative value or a value greaterthan 100, respectively. To assess assay performance and establishpositive control benchmarks, ligands listed in Table 14B were evaluatedalongside test derivative. Results for EFC-based cAMP secondarymessenger assays on GPCRs using compound C(V) ligand or positivecontrols are shown in Table 14C.

v. MAO-A Enzyme Assay.

For the MAO-A assay, all chemicals and enzyme preparations were sourcedfrom Sigma. Briefly, enzyme and test compound (i.e., derivative orcontrol compound; see Table 14B) were preincubated for 15 minutes at 37°C. before substrate addition. The reaction was initiated by addition ofkynuramine and incubated at 37° C. for 30 minutes. The reaction wasterminated by addition of NaOH. The amount of 4-hydroquinoline formedwas determined through spectrofluorometric readout with the emissiondetection at 380 nm and excitation wavelength 310 nm. For each assay,microplates were transferred to a PerkinElmer Envision™ instrument forreadouts as per standard procedures. Compound activity was analyzedusing CBIS data analysis suite (ChemInnovation, CA). Percentageinhibition was calculated using the following formula: %inhibition=100%×[1−[mean RLU of test sample−mean RLU of vehiclecontrol]/[mean RLU of positive control−mean RLU of vehicle control]].For primary screens, percent response was capped at 0% or 100% wherecalculated percent response returned a negative value or a value greaterthan 100, respectively. To assess assay performance and establishpositive control benchmarks, ligands listed in Table 14B were evaluatedalongside test derivative. Results for EFC-based cAMP secondarymessenger assays on GPCRs using compound C(V) ligand or positivecontrols are shown in Table 14C.

TABLE 14B Control ligands used for target assays (GPCR, G-proteincoupled receptor; IC, ion channel; EN, enzyme; TR, transporter). TargetAssay Type Control ligand/modulator ADRA1A Agonist GPCR A 61603Hydrobromide ADRA1A Antagonist GPCR Tamsulosin ADRA2A Agonist GPCR UK14304 ADRA2A Antagonist GPCR Yohimbine AVPR1A Agonist GPCR[Arg8]-Vasopressin AVPR1A Antagonist GPCR SR 49059 CHRM1 Agonist GPCRAcetylcholine chloride CHRM1 Antagonist GPCR Atropine CHRM2 Agonist GPCRAcetylcholine chloride CHRM2 Antagonist GPCR Atropine CNR1 Agonist GPCRCP 55940 CNR1 Antagonist GPCR AM 251 DRD1 Agonist GPCR Dopamine DRD1Antagonist GPCR SCH 39166 DRD2S Agonist GPCR Dopamine DRD2S AntagonistGPCR Risperidone HTR1A Agonist GPCR Serotonin hydrochloride HTR1AAntagonist GPCR Spiperone HTR1B Agonist GPCR Serotonin hydrochlorideHTR1B Antagonist GPCR SB 224289 HTR2B Agonist GPCR Serotoninhydrochloride HTR2B Antagonist GPCR LY 272015 OPRD1 Agonist GPCR DADLEOPRD1 Antagonist GPCR Naltriben GABAA Opener IC GABA GABAA Blocker ICPicrotoxin HTR3A Opener IC Serotonin hydrochloride HTR3A Blocker ICBemesetron MAO-A Inhibitor EN Clorgyline DAT Blocker TR GBR 12909 NETBlocker TR Desipramine SERT Blocker TR Clomipramine NMDAR Blocker IC(±)-MK 801 NMDAR Opener IC L-Glutamic acid

TABLE 14C Data summary table of target assays for compound C(V) andcontrol ligands. Assay EC₅₀ IC₅₀ EC₅₀ IC₅₀ Target name Target type type(control) (control) (C-V) (C-V) ADRA1A GPCR AGN 5.00E−05 — >100 — ADRA1AGPCR ANT — 9.60E−04 — 14.93 ADRA2A GPCR AGN 4.00E−05 — >100 — ADRA2AGPCR ANT — 3.10E−03 — >100 AVPR1A GPCR AGN 4.20E−04 — >100 — AVPR1A GPCRANT — 1.60E−03 — >100 CHRM1 GPCR AGN 9.70E−03 — >100 — CHRM1 GPCR ANT —6.10E−03 — >100 CHRM2 GPCR AGN 2.70E−02 — >100 — CHRM2 GPCR ANT —3.20E−03 — >100 CNR1 GPCR AGN 1.00E−05 — >100 — CNR1 GPCR ANT — 6.20E−04— >100 DRD1 GPCR AGN 9.10E−02 — >100 — DRD1 GPCR ANT — 7.10E−04 — 12.03DRD2S GPCR AGN 5.10E−04 — >100 — DRD2S GPCR ANT — 9.60E−04 — 1.78 HTR1AGPCR AGN 1.70E−03 — 7.08 — HTR1A GPCR ANT — 4.60E−02 — >100 HTR1B GPCRAGN 9.00E−05 — 2.90E−01 — HTR1B GPCR ANT — 5.80E−03 — >100 HTR2B GPCRAGN 6.30E−04 — >100 — HTR2B GPCR ANT — 4.00E−04 — 1.20E−02 OPRD1 GPCRAGN 5.00E−05 — 51.46 — OPRD1 GPCR ANT — 5.80E−04 — >100 GABAA Ionchannel OP 6.2 — >100 — GABAA Ion channel BL — 4.6 — >100 HTR3A Ionchannel OP 3.00E−01 — >100 — HTR3A Ion channel BL — 1.90E−03 — 33.89MAO-A Enzyme IN — 2.90E−03 — 76.01 DAT transporter BL — 1.40E−03 — >100NET transporter BL — 6.70E−03 — >100 SERT transporter BL — 1.80E−03— >100 NMDAR Ion channel BL — 8.00E−02 — >100 NMDAR Ion channel OP4.40E−01 — >100 — Potency (EC₅₀ or IC₅₀) is provided in units of μM.AGN, agonist; ANT, antagonist; OP, opener; BL, blocker; IN, inhibitor.

Example 2—Synthesis and Analysis of a Second C₄-CarboxylicAcid-Substituted Tryptamine Derivative

The synthesis of psilocin (1) has been described previously (Shirota etal., J. Nat. Prod. 2003, 66:885-887; Kargbo et al., ACS Omega 2020,5:16959-16966). Referring to FIG. 4A, to a suspension of compound (1)(30 mg) in dry dichloromethane (DCM) (8 ml) was added 22 μl oftriethylamine dropwise, and pentafluorobenzoyl chloride (34.6 μl). Afterstirring for 5 minutes at room temperature, the mixture turned to clearsolution. The mixture was stirred at room temperature for 1-2 hours andthe reaction was monitored by thin layer chromatography (TLC). Thereaction was then quenched by diluted aqueous HCl (0.5N) and extractedby DCM three times. The combined organic extracts were washed withwater, brine and dried over anhydrous MgSO₄. After concentration byrotary evaporator, the mixture residue was applied to a silica columnfor chromatographic purification and eluted using 5% methanol in DCM toafford compound (3) as an off-white solid (21.2 mg, 36% yield). 1H NMR(CDCl₃) δ 7.38 (2H, m, ArH), 7.21 (1H, t, ArH), 6.94 (1H, dd, ArH), 3.45(2H, dd, CH2), 3.37 (2H, m, CH2), 2.87 (6H, s, 2×NCH₃). LCMS result: calmass for C₁₉H₁₆FN₂O₂ [M+H]: 399.1126. found: 399.1120. Purity wasdetermined to be 95%. It is noted that compound (3) corresponds with thechemical compound having chemical formula C(VI):

Assessment of Cell Viability Upon Treatment of a Psilocin Derivative.

Cell viability was assessed as described for Example 1, except thecompound with formula C(VI) was evaluated in place of the compound withformula C(V). Data acquired for the derivative having chemical formula(C-V) is displayed as “C-V” on the x-axes in FIG. 4B and FIG. 4C.

Radioligand Receptor Binding Assays.

Activity at 5-HT_(2A) receptor was assessed as described for Example 1,except the compound with formula C(VI) was evaluated in place of thecompound with formula C(V). FIG. 4D shows radioligand competition assayresults for compound with formula C(VI), depicted on the x-axis simplyas “C-VI”.

Cell Lines and Control Ligands Used to Assess Activity at 5-HT_(1A).

Cell lines, cell line maintenance, and experimental procedures assessingmodulation of 5-HT_(1A) were performed as described in Example 1, exceptthat compound C(VI) was evaluated in place of compound C(V). 5-HT_(1A)receptor binding evaluation for compound with formula C(VI) (designatedsimply “C-VI” along the x-axis) is shown in FIG. 4E. Comparison of dataacquired in +5-HT_(1A) cultures with those acquired in −5-HT_(1A)cultures suggests no receptor modulation at higher ligandconcentrations.

Evaluation of Metabolic Stability in Human Intestine, Liver, and SerumFractions In Vitro.

Evaluations of metabolic stability and capacity of novel molecules torelease psilocin under various in vitro conditions were performed asdescribed in Example 1, except that compound C(VI) was used in place ofcompound C(V) for all experiments. FIGS. 4F (i)-4F (iii) show themetabolic stability curves for compound with formula C(VI), designated“C-VI,” in control buffer (Panel A), AB serum (Panel B), HIM (Panel C),HLM (Panel D), HIS9 (Panel E), HLS9 (Panel F), alkaline phosphatase(Panel G), and esterase (Panel H).

In Vivo Evaluation of 5-HT_(2A) Receptor Agonism in Mice.

Evaluation of in vivo HTR was conducted as described in Example 1,except that compound C(VI) was used in place of compound C(V). Elevatedincidences of HTR within the defined period of monitoring was observedin (1) psilocybin-treated mice, and (2) those treated with compound“C-VI,” relative to control mice treated with i.p. injected vehicle(0.9% NaCl). These results are illustrated in FIG. 4G, wherein compoundwith formula C(VI) is designated “C-VI.”

Mouse Pharmacokinetic (PK) Evaluation of Drug Metabolism to Psilocin.

Pharmacokinetic (PK) evaluations were performed in the same manner asdescribed in Example 1, except compound C(VI) was used in place ofcompound C(V). Notably, compound C(VI) was not detectable in any animalsat any dose, suggesting a degree of instability and/or quick conversionto psilocin. Thus, only psilocin PK analysis was performed.

Results for psilocin PK following C(VI) administration are found inTables 15A-15B (1 mg/kg IV dose), Tables 16A-16B (1 mg/kg oral dose),Tables 17A-17B (3 mg/kg oral dose), Tables 18A-18B (10 mg/kg oral dose),Table 19 (comparative summary for IV data), Table 20 (comparativesummary for oral data), Table 21A (psilocin exposure) and FIGS. 4H (i)and 4H (ii).

TABLE 15A Plasma concentrations of psilocin following 1 mg/kg i.v.administration of C(VI). Experimental Plasma concentration (ng/ml) time(h) M01 M02 M03 Mean ± SD 0.0833 26.7 35.4 35.2 32.4 ± 4.97 0.25 24.636.2 28.6 29.8 ± 5.89 0.5 11.6 12.6 8.66 11.0 ± 2.05 1 4.58 4.62 3.52 4.24 ± 0.624 2 1.34 1.91 1.13  1.46 ± 0.404 4 0.506 0.446 0.513  0.488± 0.0368 6 0.172 0.216 0.236  0.208 ± 0.0327 8 BLQ BLQ BLQ n/a BLQdenotes below the lower limit of quantitation (0.2 ng/ml). n/a denotesnot applicable.

TABLE 15B Summary of plasma PK parameters for psilocin following 1 mg/kgi.v. administration of C(VI)^(a). Parameter estimate for each animalParameter M01 M02 M03 Mean ± SD t_(max) (h) 0.0833 0.250 0.0833  0.139 ±0.0962 C_(max) (ng/ml) 26.7 36.2 35.2 32.7 ± 5.22 C_(max)/Dose^(a) 26.736.2 35.2 32.7 ± 5.22 (kg*ng/ml/mg) Apparent t_(1/2) (h) 1.35 1.27 1.77 1.46 ± 0.268 AUC_(0-tlast) 18.5 22.7 18.2 19.8 ± 2.55 (h*ng/mL)AUC_(0-tlast)/Dose^(a) 18.5 22.7 18.2 19.8 ± 2.55 (h*kg*ng/mL/mg)AUC_(0-inf) 18.8 23.1 18.8 20.2 ± 2.51 (h*ng/mL) MRT_(0-inf) (h) 1.020.954 1.10   1.02 ± 0.0705 ^(a)C(VI) dose was used.

TABLE 16A Plasma concentrations of psilocin following 1 mg/kg oraladministration of C(VI). Experimental Plasma concentration (ng/ml) time(h) M04 M05 M06 Mean ± SD 0.25 334 8.80 10.6  9.70 (n = 2) 0.5 7.79 9.628.81  8.74 ± 0.917 1 4.38 5.09 5.15  4.87 ± 0.428 2 2.11 0.922 2.08 1.70 ± 0.677 4 0.666 0.296 0.212 0.391 ± 0.242 6 0.372 0.158 0.1970.242 ± 0.114 8 0.274 BLQ BLQ 0.274 (n = 1) 24 BLQ No Peak No Peak n/aBolded value is considered an outlier and was excluded fromcalculations. BLQ denotes below the lower limit of quantitation (0.2ng/ml). Value in italics is below the lower limit of quantitation (BLQ,0.2 ng/ml) but was included in calculations. n/a denotes not applicable.

TABLE 16B Summary of plasma PK parameters for psilocin following 1 mg/kgoral administration of C(VI)^(a). Parameter estimate for each animalParameter M04 M05 M06 Mean ± SD t_(max) (h) 0.500 0.500 0.250 0.417 ±0.144 C_(max) (ng/ml) 7.79 9.62 10.6 9.34 ± 1.43 C_(max)/Dose^(a) 7.799.62 10.6 9.34 ± 1.43 (kg*ng/ml/mg) Apparent t_(1/2) (h) 3.12 1.57 0.9991.90 ± 1.10 AUC_(0-tlast) (h*ng/mL) 12.2 10.9 12.6  11.9 ± 0.854AUC_(0-tlast)/Doseª 12.2 10.9 12.6  11.9 ± 0.854 (h*kg*ng/mL/mg)AUC_(0-inf) (h*ng/mL) 13.4 11.3 12.9 12.5 ± 1.09 MRT_(0-inf) (h) 2.941.35 1.32  1.87 ± 0.928 ^(a)C(VI) dose was used.

TABLE 17A Plasma concentrations of psilocin following 3 mg/kg oraladministration of C(VI). Experimental Plasma concentration (ng/ml) time(h) M07 M08 M09 Mean ± SD 0.25 21.5 31.3 35.2 29.3 ± 7.06 0.5 27.8 28.027.2  27.7 ± 0.416 1 20.1 11.9 22.0 18.0 ± 5.37 2 6.01 6.20 6.44  6.22 ±0.215 4 0.865 0.912 0.843  0.873 ± 0.0352 6 0.640 0.556 0.455  0.550 ±0.0926 8 0.133 0.129 0.118   0.127 ± 0.00777 24 BLQ BLQ No Peak n/a BLQdenotes below the lower limit of quantitation (0.2 ng/ml). n/a denotesnot applicable.

TABLE 17B Summary of plasma PK parameters for psilocin following 3 mg/kgoral administration of C(VI). Parameter estimate for each animalParameter M07 M08 M09 Mean ± SD t_(max) (h) 0.500 0.250 0.250 0.333 ±0.144 C_(max) (ng/ml) 27.8 31.3 35.2 31.4 ± 3.70 C_(max)/Dose^(a) 9.2710.4 11.7 10.5 ± 1.23 (kg*ng/ml/mg) Apparent t_(1/2) (h) 1.48 1.42 1.41 1.44 ± 0.0388 AUC_(0-tlast) 39.8 37.0 44.3 40.4 ± 3.70 (h*ng/mL)AUC_(0-tlast)/Dose^(a) 13.3 12.3 14.8 13.5 ± 1.23 (h*kg*ng/ml/mg)AUC_(0-inf) (h*ng/mL) 40.1 37.3 44.6 40.7 ± 3.68 MRT_(0-inf) (h) 1.421.39 1.29  1.37 ± 0.0690 ^(a)C(VI) dose was used.

TABLE 18A Plasma concentrations of psilocin following 10 mg/kg oraladministration of C(VI). Experimental Plasma concentration (ng/mL) time(h) M10 M11 M12 Mean ± SD 0.25 66.6 55.1 95.9 72.5 ± 21.0 0.5 56.4 51.3105 70.9 ± 29.6 1 30.5 39.3 46.8 38.9 ± 8.16 2 17.3 18.4 21.1 18.9 ±1.96 4 4.96 3.98 2.34 3.76 ± 1.32 6 1.27 1.03 2.39  1.56 ± 0.726 8 0.7090.461 0.477 0.549 ± 0.139 24 BLQ BLQ BLQ n/a BLQ denotes below the lowerlimit of quantitation (0.2 ng/ml). n/a denotes not applicable.

TABLE 18B Summary of plasma PK parameters for psilocin following 10mg/kg oral administration of C(VI)^(a). Parameter estimate for eachanimal Parameter M10 M11 M12 Mean ± SD t_(max) (h) 0.250 0.250 0.5000.333 ± 0.144 C_(max) (ng/ml) 66.6 55.1 105 75.6 ± 26.1 C_(max)/Dose^(a)6.66 5.51 10.5 7.56 ± 2.61 (kg*ng/ml/mg) Apparent t_(1/2) (h) 1.27 1.121.22  1.20 ± 0.0768 AUC_(0-tlast) 95.1 94.9 130 107 ± 20.0 (h*ng/mL)AUC_(0-tlast)/Dose^(a) 9.51 9.49 13.0 10.7 ± 2.00 (h*kg*ng/mL/mg)AUC_(0-inf) 96.4 95.6 130 107 ± 19.9 (h*ng/mL) MRT_(0-inf) (h) 1.70 1.601.36  1.55 ± 0.172 ^(a)C(VI) dose was used.

TABLE 19 Comparative summary of psilocin pharmacokinetic (PK) parametersfollowing intravenous (IV) dosing of psilocybin or compound C(VI)^(a).Parameter Psilocybin C(VI) Nominal prodrug dose 1 1 (mg/kg) t_(max) (h) 0.139 ± 0.0962  0.139 ± 0.0962 C_(max) (ng/mL)  105 ± 19.8 32.7 ± 5.22C_(max)/Dose^(a)  105 ± 19.8 32.7 ± 5.22 (kg*ng/ml/mg) Apparent t_(1/2)(h) 0.905 (n = 1)  1.46 ± 0.268 AUC_(0-tlast) (h*ng/mL) 89.8 ± 17.5 19.8± 2.55 AUC_(0-tlast)/Dose^(a) 89.8 ± 17.5 19.8 ± 2.55 (h*kg*ng/mL/mg)AUC_(0-inf) (h*ng/mL)   110 (n = 1) 20.2 ± 2.51 MRT_(0-inf) (h)  1.64 (n= 1)   1.02 ± 0.0705 ^(a)Prodrug dose was used.

TABLE 20 Comparative summary of psilocin pharmacokinetic (PK) parametersfollowing oral (PO) dosing of psilocybin or compound C(VI). ParameterPsilocybin C(VI) Nominal prodrug dose 1 3 10 1 3 10 (mg/kg) t_(max) (h)0.333 ± 0.144 0.417 ± 0.144 0.333 ± 0.144 0.417 ± 0.144 0.333 ± 0.1440.333 ± 0.144 C_(max) (ng/mL) 53.7 ± 3.50 52.9 ± 10.5  243 ± 43.7 9.34 ±1.43 31.4 ± 3.70 75.6 ± 26.1 C_(max)/Dose^(a) 1.56 17.6 ± 3.48 24.3 ±4.37 9.34 ± 1.43 10.5 ± 1.23 7.56 ± 2.61 (kg * ng/mL/mg) Apparentt_(1/2) (h) 2.15 4.51  3.58 ± 0.920 1.90 ± 1.10  1.44 ± 0.0388  1.20 ±0.0768 (n = 1) (n = 2) AUC_(0-tlast) (h * ng/mL) 67.1 ± 1.61 84.4 ± 10.8 397 ± 55.5  11.9 ± 0.854 40.4 ± 3.70  107 ± 20.0 AUC_(0-tlast)/Dose^(a)34.4 ± 2.24 28.1 ± 3.61 39.7 ± 5.55  11.9 ± 0.854 13.5 ± 1.23 10.7 ±2.00 (h * kg * ng/mL/mg) AUC_(0-inf) (h * ng/mL) 70.4 80.5  398 ± 55.112.5 ± 1.09 40.7 ± 3.68  107 ± 19.9 (n = 1) (n = 2) MRT_(0-inf) (h) 1.532.04  2.39 ± 0.236  1.87 ± 0.928  1.37 ± 0.0690  1.55 ± 0.172 (n = 1) (n= 2)

TABLE 21A Summary of mean plasma exposure of psilocin as a function ofC(VI) dose. C(VI) dose Parameter 1 mg/kg i.v. 1 mg/kg p.o. 3 mg/kg p.o.10 mg/kg p.o. C_(max)/Dose^(a) 32.7 ± 5.22 9.34 ± 1.43 10.5 ± 1.23 7.56± 2.61 (kg*ng/ml/mg) Apparent t_(1/2) (h)  1.46 ± 0.268 1.90 ± 1.10  1.44 ± 0.0388   1.20 ± 0.0768 AUC_(0-tlast)/Doseª 19.8 ± 2.55  11.9 ±0.854 13.5 ± 1.23 10.7 ± 2.00 (h*kg*ng/ml/mg)

In Vitro Survey of Pharmacological Interaction Profiles at Receptors,Transporters and Enzymes Linked to Targeted Health Conditions.

All assays were performed as described in Example 1, except compoundC(VI) was used in place of CMV. To assess assay performance andestablish positive control benchmarks, ligands listed in Table 14B wereevaluated alongside test derivative. Results for all assays usingcompound C(VI) or positive controls are shown in Table 21B.

TABLE 21B Data summary table of target assays for compound C(VI) andcontrol ligands. Assay EC₅₀ IC50 EC50 IC50 Target name Target type type(control) (control) (C-VI) (C-VI) ADRA1A GPCR AGN 5.00E−05 — 34.41 —ADRA1A GPCR ANT — 9.60E−04 — 26.88 ADRA2A GPCR AGN 4.00E−05 — 65.08 —ADRA2A GPCR ANT — 3.10E−03 — >100 AVPR1A GPCR AGN 4.20E−04 — >100 —AVPR1A GPCR ANT — 1.60E−03 — >100 CHRM1 GPCR AGN 9.70E−03 — >100 — CHRM1GPCR ANT — 6.10E−03 — >100 CHRM2 GPCR AGN 2.70E−02 — >100 — CHRM2 GPCRANT — 3.20E−03 — >100 CNR1 GPCR AGN 1.00E−05 — 62.92 — CNR1 GPCR ANT —6.20E−04 — >100 DRD1 GPCR AGN 9.10E−02 — >100 — DRD1 GPCR ANT — 7.10E−04— 51.63 DRD2S GPCR AGN 5.10E−04 — 1.09 — DRD2S GPCR ANT — 9.60E−04— >100 HTR1A GPCR AGN 1.70E−03 — 2.21 — HTR1A GPCR ANT — 4.60E−02 — >100HTR1B GPCR AGN 9.00E−05 — 1.00E−01 — HTR1B GPCR ANT — 5.80E−03 — >100HTR2B GPCR AGN 6.30E−04 — >100 — HTR2B GPCR ANT — 4.00E−04 — 0.03 OPRD1GPCR AGN 5.00E−05 — 59.41 — OPRD1 GPCR ANT — 5.80E−04 — >100 GABAA Ionchannel OP 6.2 — >100 — GABAA Ion channel BL — 4.6 — >100 HTR3A Ionchannel OP 3.00E−01 — >100 — HTR3A Ion channel BL — 1.90E−03 — 55.13MAO-A Enzyme IN — 2.90E−03 — 20.68 DAT transporter BL — 1.40E−03 — >100NET transporter BL — 6.70E−03 — >100 SERT transporter BL — 1.80E−03 —34.29 NMDAR Ion channel BL — 8.00E−02 — >100 NMDAR Ion channel OP4.40E−01 — >100 — Potency (EC₅₀ or IC₅₀) is provided in units of μM.AGN, agonist; ANT, antagonist; OP, opener; BL, blocker; IN, inhibitor.

Example 3—Synthesis and Analysis of a Third C₄-CarboxylicAcid-Substituted Tryptamine Derivative

The synthesis of psilocin (1) has been described previously (Shirota etal., J. Nat. Prod. 2003, 66:885-887; Kargbo et al., ACS Omega 2020,5:16959-16966). Referring to FIG. 5A, to a flame-dried flask was addedcompound (1) (50 mg, 0.25 mmol, 2.0 eq), and anhydrous dichloromethane(DCM) (1 mL) under argon. Triethylamine (34 μL, 0.25 mmol, 2.0 eq) wasadded, followed by isophthaloyl chloride (25 mg, 0.12 mmol, 1.0 eq)dissolved in anhydrous dichloromethane (1 mL). The mixture was refluxedovernight, then directly purified using flash chromatography on 4 gnormal-phase silica and eluted with a 10-20% (methanol-dichloromethane)gradient to afford compound (4) (19.6 mg, 30% yield) as a tan oil. ¹HNMR (400 MHz, methanol-d4) δ 9.13 (td, J=1.8, 0.6 Hz, 1H), 8.70 (dd,J=7.8, 1.8 Hz, 2H), 7.95 (td, J=7.8, 0.6 Hz, 1H), 7.42-7.37 (m, 2H),7.29 (t, J=0.9 Hz, 2H), 7.24-7.18 (m, 2H), 6.93 (dd, J=7.7, 0.8 Hz, 2H),3.41-3.36 (m, 4H), 3.20-3.14 (m, 4H), 2.73 (s, 12H). Purity wasdetermined to be 95%. It is noted that compound (4) corresponds with thechemical compound having chemical formula C(VII):

Assessment of Cell Viability Upon Treatment of a Psilocin Derivative.

Cell viability was assessed as described for Example 1, except thecompound with formula C(VII) was evaluated in place of the compound withformula C(V). Data acquired for the derivative having chemical formula(C-VII) is displayed as “C-VII” on the x-axis in FIG. 5B.

Radioligand Receptor Binding Assays.

Activity at 5-HT_(2A) receptor was assessed as described for Example 1,except the compound with formula C(VII) was evaluated in place of thecompound with formula C(V). FIG. 5C shows radioligand competition assayresults for compound with formula C(VII), depicted on the x-axis simplyas “C-VII”.

Cell Lines and Control Ligands Used to Assess Activity at 5-HT_(1A).

Cell lines, cell line maintenance, and experimental procedures assessingmodulation of 5-HT_(1A) were performed as described in Example 1, exceptthat compound C(VII) was evaluated in place of compound C(V). 5-HT_(1A)receptor binding evaluation for compound with formula C(VII) (designatedsimply “C-VII” along the x-axis) is shown in FIG. 5D. Comparison of dataacquired in +5-HT_(1A) cultures with those acquired in −5-HT_(1A)cultures suggests no significant receptor modulation.

Evaluation of Metabolic Stability in Human Intestine, Liver, and SerumFractions In Vitro.

Evaluations of metabolic stability and capacity of novel molecules torelease psilocin under various in vitro conditions were performed asdescribed in Example 1, except that compound C(VII) was used in place ofcompound C(V) for all experiments. FIGS. 5E (i) and 5E (ii) shows themetabolic stability curves for compound with formula C(VII), designated“C-VII” in assays containing HLM (Panel A), HLS9 (Panel B), HIM (PanelC), HIS9 (Panel D), AB serum (Panel E) and Esterase (Panel F).

In Vivo Evaluation of 5-HT_(2A) Receptor Agonism in Mice.

Evaluation of in vivo HTR was conducted as described in Example 1,except that compound C(VII) was used in place of compound C(V). Elevatedincidences of HTR within the defined period of monitoring was observedin (1) psilocybin-treated mice, and (2) those treated with compound“C-VII,” relative to control mice treated with i.p. injected vehicle(0.9% NaCl). These results are illustrated in FIG. 5F, wherein compoundwith formula C(VII) is designated simply “C-VII.” Results for controlmice injected with vehicle are not shown in FIG. 5F, but are the same asthose in Examples 1 and 2 since HTR experiments were run with the samecontrol cohorts.

Example 4—Synthesis and Analysis of a Fourth C₄-CarboxylicAcid-Substituted Tryptamine Derivative

The synthesis of psilocin (1) has been described previously (Shirota etal., J. Nat. Prod. 2003, 66:885-887; Kargbo et al., ACS Omega 2020,5:16959-16966). Referring to FIG. 6A, Compound (1) (100 mg, 0.49 mmol,1.0 eq) was suspended in anhydrous dichloromethane (DCM) (0.5 mL) underargon atmosphere. Triethylamine (0.10 mL, 0.73 mmol, 1.5 eq) was added,followed by m-PEG2-CH₂ acid chloride (96 mg, 0.49 mmol, 1.0 eq) dilutedwith anhydrous dichloromethane (0.2 mL). The resulting mixture wasstirred at room temperature for 23 hours and monitored by TLC (20%methanol/dichloromethane). Solvent was removed under reduced pressure,and the crude mixture was purified by flash column chromatography on 12g normal-phase silica using 10% methanol/dichloromethane as eluent. Theresulting crude product was further purified by flash columnchromatography on 4 g normal-phase silica using an 8 to 10%methanol/dichloromethane gradient as eluent to yield (11) (3.9 mg, 2.2%yield) as a colourless oil. ¹H NMR (400 MHz, methanol-d4) δ 7.32 (dd,J=8.2, 0.8 Hz, 1H), 7.27 (s, 1H), 7.15 (t, J=8.0 Hz, 1H), 6.88 (dd,J=7.8, 0.8 Hz, 1H), 4.58 (s, 2H), 3.92-3.85 (m, 2H), 3.78-3.72 (m, 2H),3.70-3.64 (m, 2H), 3.59-3.52 (m, 2H), 3.48-3.42 (m, 2H), 3.37 (s, 3H),3.26-3.17 (m, 3H), 2.94 (s, 6H). Purity was determined to be 95%. It isnoted that compound (11) corresponds with the chemical compound havingchemical formula C(III):

Assessment of Cell Viability Upon Treatment of a Psilocin Derivative.

Cell viability was assessed as described for Example 1, except thecompound with formula C(III) was evaluated in place of the compound withformula C(V). Data acquired for the derivative having chemical formula(C-III) is displayed as “C-III” on the x-axes of FIG. 6B and FIG. 6C.

Radioligand Receptor Binding Assays.

Activity at 5-HT_(2A) receptor was assessed as described for Example 1,except the compound with formula C(III) was evaluated in place of thecompound with formula C(V). FIG. 6D shows radioligand competition assayresults for compound with formula C(III), depicted on the x-axis simplyas “C-III”.

Cell Lines and Control Ligands Used to Assess Activity at 5-HT_(1A).

Cell lines, cell line maintenance, and experimental procedures assessingmodulation of 5-HT_(1A) were performed as described in Example 1, exceptthat compound C(III) was evaluated in place of compound C(V). 5-HT_(1A)receptor binding evaluation for compound with formula C(III) (designatedsimply “C-III” along the x-axis) is shown in FIG. 6E. Comparison of dataacquired in +5-HT_(1A) cultures with those acquired in −5-HT_(1A)cultures suggests significant receptor modulation.

Evaluation of Metabolic Stability in Human Intestine, Liver, and SerumFractions In Vitro.

Evaluations of metabolic stability and capacity of novel molecules torelease psilocin under various in vitro conditions were performed asdescribed in Example 1, except that compound C(III) was used in place ofcompound C(V) for all experiments. FIGS. 6F (i)-6F (ii) show themetabolic stability curves for compound with formula C(III), designated“C-III” in assays containing HLM (Panel A), HLS9 (Panel B), HIM (PanelC), HIS9 (Panel D), AB serum (Panel E) and Buffer (Panel F).

In Vivo Evaluation of 5-HT_(2A) Receptor Agonism in Mice.

Evaluation of in vivo HTR was conducted as described in Example 1,except that compound C(III) was used in place of compound C(V). Elevatedincidences of HTR within the defined period of monitoring was observedin (1) psilocybin-treated mice, and (2) those treated with compound“C-III,” relative to control mice treated with i.p. injected vehicle(0.9% NaCl). These results are illustrated in FIG. 6G, wherein compoundwith formula C(III) is designated simply “C-III.” Results for controlmice injected with vehicle are not shown in FIG. 6F, but are the same asthose in Examples 1 and 2 since HTR experiments were run with the samecontrol cohorts.

Example 5—Synthesis and Analysis of a Fifth C₄-CarboxylicAcid-Substituted Tryptamine Derivative

The synthesis of psilocin (1) has been described previously (Shirota etal., J. Nat. Prod. 2003, 66:885-887; Kargbo et al., ACS Omega 2020,5:16959-16966). Referring to FIG. 7A, to a suspension of compound 1 (102mg, 0.50 mmol, 2.0 eq) in dry DCM (1.5 mL) under argon atmosphere wasadded triethylamine (70 μL, 0.50 mmol, 2.0 eq) followed by isophthaloyldichloride (51 mg, 0.25 mmol, 1.0 eq) dissolved in dry DCM (0.5 mL). Thereaction mixture was allowed to stir at room temperature for 18 hours.The crude reaction mixture was directly purified via flashchromatography on 4 g normal-phase silica and eluted with a 10 to 20%methanol-dichloromethane gradient to yield a mixture of products. Thismixture was further purified by flash column chromatography on 4 gnormal-phase silica and eluted with 10% methanol-dichloromethane toyield compound 13 (7 mg, 8%) as a colourless oil. The calculated MS-ESIvalue was 367.1652, compared with observed value 367.1650 m/z [M+H]⁺. ¹HNMR (400 MHz, MeOD) δ 8.91 (td, J=1.8, 0.6 Hz, 1H), 8.54 (ddd, J=7.8,1.8, 1.2 Hz, 1H), 8.40 (dt, J=7.9, 1.4 Hz, 1H), 7.80 (td, J=7.8, 0.6 Hz,1H), 7.38 (dd, J=8.2, 0.8 Hz, 1H), 7.27 (d, J=0.8 Hz, 1H), 7.21 (t,J=7.9 Hz, 1H), 6.91 (dd, J=7.7, 0.8 Hz, 1H), 4.00 (s, 3H), 3.29 (dd,J=8.6, 6.8 Hz, 2H), 3.12-3.06 (m, 2H), 2.65 (s, 6H). Purity wasdetermined to be 95%. Continuing to refer to FIG. 7A, it is noted thatcompound 13 corresponds with the chemical compound having chemicalformula C(XLIII):

Assessment of Cell Viability Upon Treatment of a Psilocin Derivative.

Cell viability was assessed as described for Example 1, except thecompound with formula C(XLIII) was evaluated in place of the compoundwith formula C(V). Data acquired for the derivative having chemicalformula (C-XLIII) is displayed as “C-XLIII” on the x-axes of FIG. 7B andFIG. 7C.

Radioligand Receptor Binding Assays.

Activity at 5-HT_(2A) receptor was assessed as described for Example 1,except the compound with formula C(XLIII) was evaluated in place of thecompound with formula C(V). FIG. 7D shows radioligand competition assayresults for compound with formula C(XLIII), depicted on the x-axissimply as “C-XLIII”.

Cell Lines and Control Ligands Used to Assess Activity at 5-HT_(1A).

Cell lines, cell line maintenance, and experimental procedures assessingmodulation of 5-HT_(1A) were performed as described in Example 1, exceptthat compound C(XLIII) was evaluated in place of compound C(V).5-HT_(1A) receptor binding evaluation, including EC₅₀ for compound withformula C(XLIII) (designated simply “C-XLIII” along the x-axis) is shownin FIG. 7E. Comparison of data acquired in +5-HT_(1A) cultures withthose acquired in −5-HT_(1A) cultures suggests receptor modulation athigher ligand concentrations.

Evaluation of Metabolic Stability in Human Intestine, Liver, and SerumFractions In Vitro.

Evaluations of metabolic stability and capacity of novel molecules torelease psilocin under various in vitro conditions were performed asdescribed in Example 1, except that compound C(XLIII) was used in placeof compound C(V) for all experiments. FIGS. 7F (i) and 7F(ii) shows themetabolic stability curves for compound with formula C(XLIII),designated “C-XLIII” in assays containing HLM (Panel A), HLS9 (Panel B),HIM (Panel C), HIS9 (Panel D), AB serum (Panel E) and Buffer (Panel F).

Example 6—Synthesis and Analysis of a Sixth C₄-CarboxylicAcid-Substituted Tryptamine Derivative

This Example 6 initially describes an example method for synthesis of anexample C₄-carboxylic acid substituted tryptamine derivative, notably acompound having chemical formula C(I). Referring to FIG. 8A, a dry,3-neck RBF was charged with 4-benzyloxyindole (1) (14.0 g, 62.7 mmol)and Et₂O (327 mL) under Ar. The mixture was cooled down to 0° C. in anice bath. An Argon sparge was placed on the RBF and into the reactionmixture to purge out the HCl gas released from the reaction. Oxalylchloride (10.9 mL, 129 mmol) was added dropwise over 40 min, whilemaintaining the cold temperature. The mixture was stirred for 4 h at 0°C. to yield (2). The argon sparge was removed, and dimethylamine (157mL, 314 mmol) (2 M in THF) was added dropwise at 0° C. over 1 h using anaddition funnel. The mixture was allowed to warm up to RT and stirovernight. Diethyl ether (200 mL) was added, and the mixture was cooleddown to 0° C. The resulting precipitate (crude (3) was filtered andtransferred to an Erlenmeyer flask. The solid was suspended in water(300 mL) and stirred for 30 min. Then, it was filtered and washed withmore H₂O to remove residual salts. The crude solid was further dried invacuo and used in the next step without further purification.

Continuing to refer to FIG. 8A, lithium aluminum hydride (60.2 mL, 120mmol) (2M in THF) was added to a dry 3-neck flask under Argon. The flaskwas fitted with a reflux condenser and an addition funnel. Dry1,4-dioxane (100 mL) was added, and the mixture was heated to 60° C. inan oil bath. In a separate flask, compound (3) (7.46 g, 23.1 mmol) wasdissolved in a mixture of THF (60 mL) and 1,4-dioxane (120 mL). Withrapid stirring, this solution was added dropwise to the reaction flaskover 1 h using an addition funnel. The oil bath temperature was held at70° C. for 4 h, followed by vigorous reflux overnight (16 h) in an oilbath temperature of 95° C.

Continuing to refer to FIG. 8A, the reaction was placed in an ice bath,and a solution of distilled H₂O (25 mL) in THF (65 mL) was addeddropwise to quench LiAlH₄, resulting in a gray flocculent precipitate.Et₂O (160 mL) was added to assist breakup of the complex and improvefiltration. This slurry was stirred for 1 h and the mixture was thenfiltered using a Buchner funnel. The filter cake was washed on thefilter with warm Et₂O (2×200 mL) and was broken up, transferred backinto the reaction flask and vigorously stirred with additional warm Et₂O(300 mL). This slurry was filtered, and the cake was washed on thefilter with Et₂O (120 mL) and hexane (2×120 mL). All the organicfiltrates were combined and dried (MgSO₄). After the drying agent wasremoved by filtration, the filtrate was concentrated under vacuum anddried under high vacuum. The crude residue was triturated with EtOAc/hex(1:9, 25 mL) to afford the crude product (4) which was used in the nextstep without further purification.

Continuing to refer to FIG. 8A, to a solution of (4) (5.00 g, 17.0 mmol)in dry THF (100 mL) cooled to −78° C. under argon was added dropwise a 1M solution of KHMDS (18.7 mL, 18.7 mmol) in THF. After stirring at −78°C. for 1 h, a solution of TIPSCl (3.82 mL, 17.8 mmol) in THF (19.0 mL)was added dropwise over 15 minutes, and the reaction mixture was allowedto warm up to RT. After stirring at RT for 1 h, the reaction wasquenched with H₂O (40 mL), THF was evaporated under reduced pressure,and the aqueous solution was further diluted with H₂O (75 mL) andextracted with DCM (3×100 mL). The organic layers were combined andwashed with brine, dried over Na₂SO₄, filtered, and concentrated underreduced pressure. The crude product was purified by flash columnchromatography (MeOH/DCM 5:95 to 10:90) to afford the pure product as alight brown oil (6.99 g, 91%). Product (5) was confirmed as follows: ¹HNMR (400 MHz, CDCl₃) δ 7.58-7.51 (m, 2H), 7.44-7.39 (m, 2H), 7.38-7.33(m, 1H), 7.12 (dd, J=8.4, 0.8 Hz, 1H), 7.08-6.99 (m, 1H), 6.94 (s, 1H),6.60 (dd, J=7.7, 0.7 Hz, 1H), 5.20 (s, 2H), 3.12-3.04 (m, 2H), 2.67-2.58(m, 2H), 2.16 (s, 6H), 1.69 (h, J=7.5 Hz, 3H), 1.16 (d, J=7.5 Hz, 18H).

Continuing to refer to FIG. 8A, to a stirring solution of 5 (6.99 g,15.5 mmol) dissolved in EtOH, 95% (310 mL), was added 10% palladium oncarbon (1.65 g, 1.55 mmol). This mixture was put under vacuum for fiveminutes, then alternately purged with H₂ gas until pressurized hydrogenatmosphere was established, then allowed to stir for 75 minutes at roomtemperature. The palladium on carbon was removed by filtration throughcelite, the filtrate dried with anhydrous magnesium sulphate, andconcentrated under reduced pressure to yield (6) (4.67 g, 84%) as anoff-white solid. Data confirming G(I) are as follows: MS-ESI:calculated: 361.2670. observed: 361.2668 m/z [M+H]⁺. ¹H NMR (400 MHz,MeOD) δ 6.98 (d, J=8.6 Hz, 2H), 6.91 (dd, J=8.4, 7.5 Hz, 1H), 6.42 (dd,J=7.5, 0.8 Hz, 1H), 3.06 (t, J=6.9 Hz, 2H), 2.77 (t, J=6.9 Hz, 2H), 2.39(s, 6H), 1.72 (p, J=7.5 Hz, 3H), 1.16 (d, J=7.5 Hz, 18H).

Continuing to refer to FIG. 8A, to a solution ofN,N-diisopropylethylamine (DIPEA) (114 μL, 653 μmol) and (6) (150 mg,416 μmol) in DCM (2.50 mL) was added, in a dropwise manner, a solutionof 4-bromobenzoyl chloride (93.2 mg, 416 μmol) in DCM (1.25 mL). Themixture was left to react at RT. After 3 hours the mixture containedvery little starting material and the reaction mixture was poured into aseparatory funnel containing 10 mL of water and 10 mL DCM. The aqueousphase was extracted with DCM (3×10 mL), all organic phases werecombined, washed with brine, and dried over magnesium sulfate.Purification was carried out by column chromatography (9:1 DCM:MeOH) toleave (7) (193 mg, 85%) as a colorless oil. Product MM-594 was confirmedas follows: MS-ESI: calculated: 543.2037. observed: 543.2036 m/z [M+H]⁺.¹H NMR (400 MHz, CDCl₃) δ 8.15 (d, J=8.6 Hz, 2H), 7.68 (d, J=8.6 Hz,2H), 7.38 (dd, J=8.3, 0.8 Hz, 1H), 7.17-7.10 (m, 1H), 7.02 (s, 1H), 6.90(dd, J=7.7, 0.7 Hz, 1H), 2.96-2.85 (m, 2H), 2.59 (t, J=8.1 Hz, 2H), 2.12(s, 6H), 1.68 (m, J=7.5 Hz, 3H), 1.14 (d, J=7.5 Hz, 18H).

Continuing to refer to FIG. 8A, To a solution of (7) (175 mg, 322 μmol)in THF (2.0 mL) was added 1.0 M tetrabutylammonium fluoride solution(483 μL, 483 μmol) dropwise. After 30 min, the mixture was poured into aseparatory funnel containing water (15 mL) and DCM (15 mL), the aqueousphase was extracted with DCM (3×15 mL), the combined organic layers werewashed with brine, dried over anhydrous MgSO4, filtered andconcentrated. The crude material was purified by column chromatography(9:1 DCM:MeOH) to provide a white powder as (8) (80.0 mg, 64%). ProductMM-597 was confirmed using the following data: MS-ESI: calculated:387.0703. observed: 387.0704 m/z [M+H]⁺. ¹H NMR (400 MHz, CDCl₃) δ 7.87(dd, J=8.2, 0.9 Hz, 1H), 7.66 (d, J=8.5 Hz, 2H), 7.58 (d, J=8.4 Hz, 2H),7.23 (d, J=8.1 Hz, 1H), 6.89 (s, 1H), 6.81 (dd, J=8.0, 0.9 Hz, 1H),2.93-2.86 (m, 2H), 2.79-2.73 (m, 2H), 2.42 (s, 6H). Purity was assessedat 95%. It is noted that compound (8) shown in FIG. 8A corresponds to acompound having chemical formula C(I):

Assessment of Cell Viability Upon Treatment of a Psilocin Derivative.

Cell viability was assessed as described for Example 1, except thecompound with formula C(I) was evaluated in place of the compound withformula C(V). Data acquired for the derivative having chemical formulaC(I) is displayed as “C-I” on the x-axes in FIG. 8B and FIG. 8C.

Radioligand Receptor Binding Assays.

Activity at 5-HT_(2A) receptor was assessed as described for Example 1,except the compound with formula C(I) was evaluated in place of thecompound with formula C(V). FIG. 8D shows radioligand competition assayresults for compound with formula C(I), depicted on the x-axis simply as“C-I”.

Cell Lines and Control Ligands Used to Assess Activity at 5-HT_(1A).

Cell lines, cell line maintenance, and experimental procedures assessingmodulation of 5-HT_(1A) were performed as described in Example 1, exceptthat compound C(I) was evaluated in place of compound C(V). 5-HT_(1A)receptor binding evaluation for compound with formula C(I) (designatedsimply “C-I” along the x-axis) is shown in FIG. 8E. Comparison of dataacquired in +5-HT_(1A) cultures with those acquired in −5-HT_(1A)cultures suggests mild receptor modulation at higher ligandconcentrations.

Evaluation of Metabolic Stability in Human Intestine, Liver, and SerumFractions In Vitro.

Evaluations of metabolic stability and capacity of novel molecules torelease psilocin under various in vitro conditions were performed asdescribed in Example 1, except that compound C(I) was used in place ofcompound C(V) for all experiments. FIGS. 8F (i)-8F(ii) show themetabolic stability curves for compound with formula C(I), designated“C-I” in assays containing HLM (Panel A), HLS9 (Panel B), HIM (Panel C),HIS9 (Panel D), AB serum (Panel E) and Buffer (Panel F).

In Vivo Evaluation of 5-HT_(2A) Receptor Agonism in Mice.

Evaluation of in vivo HTR was conducted as described in Example 1,except that compound C(I) was used in place of compound C(V). Elevatedincidences of HTR within the defined period of monitoring was observedin (1) psilocybin-treated mice, and (2) those treated with compound“C-I,” relative to control mice treated with i.p. injected vehicle (0.9%NaCl). These results are illustrated in FIG. 8G, wherein compound withformula C(I) is designated “C-I.”

Mouse Pharmacokinetic (PK) Evaluation of Drug Metabolism to Psilocin.

Pharmacokinetic (PK) evaluations were performed in the same manner asdescribed in Example 1, except compound C(I) was used in place ofcompound C(V). Results for compound C(I) PK following C(I)administration are found in Tables 22A-22B (1 mg/kg IV dose), Tables23A-23B (1 mg/kg oral dose), Tables 24A-24B (3 mg/kg oral dose), Tables25A-25B (10 mg/kg oral dose), Table 26 (C(I) exposure), and FIG. 8H.Results for psilocin PK following C(I) administration are found inTables 27A-27B (1 mg/kg IV dose), Tables 28A-28B (1 mg/kg oral dose),Tables 29A-29B (3 mg/kg oral dose), Tables 30A-30B (10 mg/kg oral dose),Table 31 (comparative summary for IV data), Table 32 (comparativesummary for oral data), Table 33A (psilocin exposure) and FIGS. 8I (i)and 8(I) (ii).

TABLE 22A Plasma concentrations of C(I) following 1 mg/kg i.v.administration of C(I). Experimental Plasma concentration (ng/ml) time(h) M37 M38 M39 Mean ± SD 0.0833 2620 118 94.4  944 ± 1450 0.25 125058.5 48.2 452 ± 691 0.5 348 33.4 30.4 137 ± 183 1 128 17.9 13.8 53.2 ±64.8 2 52.8 3.61 3.40 19.9 ± 28.5 4 8.88 0.984 0.509 3.46 ± 4.70 6 4.650.363 BLQ 2.51 (n = 2) 8 BLQ No Peak BLQ n/a Value in italics is belowthe lower limit of quantitation (BLQ, 0.5 ng/ml) but was included incalculations. BLQ denotes below the lower limit of quantitation (0.5ng/ml). n/a denotes not applicable.

TABLE 22B Summary of plasma PK parameters for C(I) following 1 mg/kgi.v. administration of C(I). Parameter estimate for each animalParameter M37 M38 M39 Mean ± SD C₀ (ng/ml) 3792 168 132 1360 ± 2100Apparent t_(1/2) (h) 1.14 1.21 0.643 0.997 ± 0.309 AUC_(0-tlast)(h*ng/mL) 1006 63.7 51.4 374 ± 548 AUC_(0-tlast)/Dose^(a) 1006 63.7 51.4374 ± 548 (h*kg*ng/ml/mg) AUC_(0-inf) (h*ng/mL) 1014 64.4 51.9 377 ± 552AUC_(0-inf)/Doseª 1014 64.4 51.9 377 ± 552 (h*kg*ng/ml/mg) CL (mL/h/kg)986 15534 19265 11900 ± 9660  MRT_(0-inf) (h) 0.568 0.780 0.657 0.668 ±0.106 V_(ss) (mL/kg) 560 12109 12650 8440 ± 6830 M37 may be consideredan outlier.

TABLE 23A Summary of plasma PK parameters for C(I) following 1 mg/kgoral administration of C(I). Experimental Plasma concentration (ng/mL)time (h) M40 M41 M42 Mean ± SD 0.25 0.617 0.410 0.910 0.646 ± 0.251 0.50.816 0.535 1.28 0.877 ± 0.376 1 0.775 BLQ 1.02 0.898 (n = 2) 2 0.474BLQ 0.600 0.537 (n = 2) 4 0.352 BLQ BLQ 0.352 (n = 1) 6 BLQ BLQ BLQ n/a8 BLQ BLQ BLQ n/a 24 No No No n/a Peak Peak Peak Value in italics isbelow the lower limit of quantitation (BLQ, 0.5 ng/ml) but was includedin calculations. BLQ denotes below the lower limit of quantitation (0.5ng/ml). n/a denotes not applicable.

TABLE 23B Summary of plasma PK parameters for C(I) following 1 mg/kgoral administration of C(I). Parameter estimate for each animalParameter M40 M41 M42 Mean ± SD t_(max) (h) 0.500 0.500 0.500 0.500 ±0.00  C_(max) (ng/ml) 0.816 0.54 1.28 0.877 ± 0.376 C_(max)/Dose 0.8160.54 1.28 0.877 ± 0.376 (kg*ng/ml/mg) Apparent t_(1/2) (h) nc^(a) nc ncn/a^(b) AUC_(0-tlast) (h*ng/mL) 2.09 0.169 1.75 1.34 ± 1.02AUC_(0-tlast)/Dose 2.09 0.169 1.75 1.34 ± 1.02 (h*kg*ng/ml/mg)AUC_(0-inf) (h*ng/mL) nc nc nc n/a MRT0-inf (h) nc nc nc n/a F(%)^(c)0.554 0.0450 0.465 0.355 ± 0.272 F(%)^(c,d) 3.59 0.291 3.01 2.30 ± 1.76^(a)nc denotes not calculable as the terminal phase is not well defined.^(b)n/a denotes not applicable ^(c)AUC_(0-tlast) was used for p.o.group, thus value might be under-estimated. ^(d)If M37 is considered asan outlier.

TABLE 24A Plasma concentrations of C(I) following 3 mg/kg oraladministration of C(I). Experimental Plasma concentration (ng/ml) time(h) M43 M44 M45 Mean ± SD 0.25 1.62 2.13 2.34 2.03 ± 0.370 0.5 1.95 2.161.99 2.03 ± 0.112 1 1.74 1.56 1.33 1.54 ± 0.206 2 0.932 0.705 0.7200.786 ± 0.127  4 0.569 0.873 1.28 0.907 ± 0.357  6 0.371 0.310 0.2500.310 ± 0.0605 8 BLQ BLQ BLQ n/a 24 No Peak No Peak No Peak n/a Valuesin italics are below the lower limit of quantitation (BLQ, 0.5 ng/ml)but were included in calculations BLQ denotes below the lower limit ofquantitation (0.5 ng/ml). n/a denotes not applicable.

TABLE 24B Summary of plasma PK parameters for C(I) following 3 mg/kgoral administration of C(I). Parameter estimate for each animalParameter M43 M44 M45 Mean ± SD t_(max) (h) 0.500 0.500 0.250 0.417 ±0.144 C_(max) (ng/ml) 1.95 2.16 2.34  2.15 ± 0.195 C_(max)/Dose 0.6500.720 0.780  0.717 ± 0.0651 (kg*ng/ml/mg) Apparent t_(1/2) (h)^(a) 3.01nc^(b) nc 3.01 (n = 1) AUC_(0-tlast) (h*ng/mL) 5.26 5.47 5.91  5.54 ±0.330 AUC_(0-tlast)/Dose 1.75 1.82 1.97  1.85 ± 0.110 (h*kg*ng/ml/mg)AUC_(0-inf) (h*ng/mL) 6.87 nc nc 6.87 (n = 1) MRT_(0-inf) (h) 4.12 nc nc4.12 (n = 1) F(%)^(c) 0.466 0.484 0.523  0.491 ± 0.0292 F(%)^(c,d) 3.023.13 3.39  3.18 ± 0.189 ^(a)For M43, apparent t_(1/2) estimate may notbe accurate; sampling interval during the terminal phase <2 × t_(1/2).^(b)nc denotes not calculable as the terminal phase is not well defined.^(c)AUC_(0-tlast) was used for p.o. group, thus value might beunder-estimated. ^(d)If M37 is considered as an outlier.

TABLE 25A Plasma concentrations of C(I) following 10 mg/kg oraladministration of C(I). Experimental Plasma concentration (ng/mL) time(h) M46 M47 M48 Mean ± SD 0.25 7.20 3.73 6.07 5.67 ± 1.77 0.5 6.41 7.1010.9 8.14 ± 2.42 1 3.79 5.29 7.46 5.51 ± 1.85 2 2.51 1.47 3.80 2.59 ±1.17 4 1.71 2.06 3.01  2.26 ± 0.673 6 0.830 1.18 0.661 0.890 ± 0.265 80.253 1.10 0.283 0.545 ± 0.481 24 No No No n/a Peak Peak Peak Values initalics are below the lower limit of quantitation (BLQ, 0.5 ng/ml) butwere included in calculations. BLQ denotes below the lower limit ofquantitation (0.5 ng/ml). n/a denotes not applicable.

TABLE 25B Summary of plasma PK parameters for C(I) following 10 mg/kgoral administration of C(I). Parameter estimate for each animalParameter M46 M47 M48 Mean ± SD t_(max) (h) 0.250 0.500 0.500 0.417 ±0.144 C_(max) (ng/ml) 7.20 7.10 10.9 8.40 ± 2.17 C_(max)/Dose 0.7200.710 1.09 0.840 ± 0.217 (kg*ng/ml/mg) Apparent t_(1/2) (h) 1.45 nc^(a)1.17 1.31 (n = 2) AUC_(0-tlast) (h*ng/mL) 15.8 16.8 23.6 18.7 ± 4.25AUC_(0-tlast)/Dose 1.58 1.68 2.36  1.87 ± 0.425 (h*kg*ng/mL/mg)AUC_(0-inf) (h*ng/mL) 16.3 n/a^(b) 24.1 20.2 (n = 2) MRT_(0-inf) (h)2.66 n/a 2.40 2.53 (n = 2) F(%)* 0.419 0.447 0.627 0.498 ± 0.113F(%)^(c,d) 2.71 2.90 4.06  3.22 ± 0.731 ^(a)nc denotes not calculable asthe terminal phase is not well defined. ^(d)If M37 is considered as anoutlier.

TABLE 26 Summary of mean plasma exposure of C(I) as a function of C(I)dose. C(I) dose 1 mg/kg 1 mg/kg 3 mg/kg 10 mg/kg Parameter i.v. p.o.p.o. p.o. C_(max)/Dose n/aª 0.877 ± 0.376 0.717 ± 0.0651 0.840 ± 0.217(kg*ng/ml/mg) Apparent t_(1/2) (h) 0.997 ± 0.309 nc^(b) 3.01 1.31 (n =2) (n = 1) AUC_(0-tlast)/Dose 57.6 1.34 ± 1.02 1.85 ± 0.110  1.87 ±0.425 (h*kg*ng/ml/mg) (n = 2) F(%) n/a 0.355 ± 0.272 0.491 ± 0.02920.498 ± 0.113 F(%)^(c) n/a 2.30 ± 1.76 3.18 ± 0.189  3.22 ± 0.731^(a)n/a denotes not applicable. ^(b)nc denotes not calculable as theterminal phase is not well defined. ^(c)M37 is considered as an outlier.

TABLE 27A Plasma concentrations of psilocin following 1 mg/kg i.v.administration of C(I). Experimental Plasma concentration (ng/ml) time(h) M37 M38 M39 Mean ± SD 0.0833 51.1 4.60 4.28 20.0 ± 26.9 0.25 43.45.18 6.01 18.2 ± 21.8 0.5 24.7 7.88 7.96 13.5 ± 9.69 1 13.5 5.17 4.827.83 ± 4.91 2 7.32 1.38 1.81 3.50 ± 3.31 4 1.55 0.393 0.386 0.776 ±0.670 6 0.645 0.183 BLQ 0.414 (n = 2) 8 0.240 BLQ BLQ 0.240 (n = 1)Value in italics is below the lower limit of quantitation (BLQ, 0.2ng/ml) but was included in calculations. BLQ denotes below the lowerlimit of quantitation (0.2 ng/ml). n/a denotes not applicable.

TABLE 27B Summary of plasma PK parameters for psilocin following 1 mg/kgi.v. administration of C(I)^(a). Parameter estimate for each animalParameter M37 M38 M39 Mean ± SD t_(max) (h) 0.0833 0.500 0.500 0.0833 ±0.00   C_(max) (ng/ml) 51.1 7.88 7.96 22.3 ± 24.9 C_(max)/Dose^(a) 51.17.88 7.96 22.3 ± 24.9 (kg*ng/ml/mg) Apparent t_(1/2) (h)^(b) 1.49 1.370.833  1.23 ± 0.349 AUC_(0-tlast) (h*ng/mL) 48.0 10.8 10.8 23.2 ± 21.4AUC_(0-tlast)/Dose^(a) 48.0 10.8 10.8 23.2 ± 21.4 (h*kg*ng/mL/mg)AUC_(0-inf) (h*ng/mL) 48.5 11.2 11.3 23.7 ± 21.5 MRT_(0-inf) (h) 1.381.53 1.33  1.41 ± 0.103 ^(a) C(I) dose. M37 may be an outlier.

TABLE 28A Plasma concentrations of psilocin following 1 mg/kg oraladministration of C(I). Experimental Plasma concentration (ng/ml) time(h) M40 M41 M42 Mean ± SD 0.25 2.13 1.84 1.96 1.98 ± 0.146 0.5 2.77 2.732.55 2.68 ± 0.117 1 1.97 1.51 1.76 1.75 ± 0.230 2 1.65 1.16 0.73 1.18 ±0.458 4 0.796 0.621 0.597 0.671 ± 0.109  6 0.252 0.421 0.250 0.308 ±0.0982 8 0.190 0.111 BLQ 0.151 (n = 2) 24 No Peak BLQ No Peak n/a Valuein italics is below the lower limit of quantitation (BLQ, 0.2 ng/ml) butwas included in calculations. BLQ denotes below the lower limit ofquantitation (0.2 ng/ml). n/a denotes not applicable.

TABLE 28B Summary of plasma PK parameters for psilocin following 1 mg/kgoral administration of C(I). Parameter estimate for each animalParameter M40 M41 M42 Mean ± SD t_(max) (h) 0.5000 0.500 0.500 0.500 ±0.00  C_(max) (ng/ml) 2.77 2.73 2.55  2.68 ± 0.117 C_(max)/Dose^(a) 2.772.73 2.55  2.68 ± 0.117 (kg*ng/ml/mg) Apparent t_(1/2) 1.82 1.87 2.59 2.09 ± 0.432 (h)^(b) AUC_(0-tlast) 7.59 6.38 5.16 6.38 ± 1.21 (h*ng/mL)AUC_(0-tlast)/Dose^(a) 7.59 6.38 5.16 6.38 ± 1.21 (h*kg*ng/mL/mg)AUC_(0-inf) 8.08 6.68 6.10 6.95 ± 1.02 (h*ng/mL) MRT_(0-inf) (h) 2.912.91 3.22  3.01 ± 0.179 ^(a)C(I) dose. ^(b)For M42, apparent t_(1/2)estimate may not be accurate; sampling interval during the terminalphase <2 × t_(1/2).

TABLE 29A Plasma concentrations of psilocin following 3 mg/kg oraladministration of C(I). Experimental Plasma concentration (ng/ml) time(h) M43 M44 M45 Mean ± SD 0.25 7.52 12.4 17.1 12.3 ± 4.79 0.5 7.35 12.712.7 10.9 ± 3.09 1 8.13 7.66 7.40  7.73 ± 0.370 2 3.11 1.82 2.60  2.51 ±0.650 4 0.940 0.626 1.49  1.02 ± 0.437 6 0.639 0.445 0.477 0.520 ± 0.1048 0.146 0.137 0.227  0.170 ± 0.0496 24 No Peak No Peak No Peak n/a Valuein italics is below the lower limit of quantitation (BLQ, 0.2 ng/ml) butwas included in calculations. BLQ denotes below the lower limit ofquantitation (0.2 ng/ml). n/a denotes not applicable.

TABLE 29B Summary of plasma PK parameters for psilocin following 3 mg/kgoral administration of C(I)^(a). Parameter estimate for each animalParameter M43 M44 M45 Mean ± SD t_(max) (h) 1.00 0.500 0.250 0.583 ±0.382 C_(max) (ng/ml) 8.13 12.7 17.1 12.6 ± 4.49 C_(max)/Dose^(a) 2.714.23 5.70 4.21 ± 1.50 (kg*ng/ml/mg) Apparent t_(1/2) (h) 1.45 1.71 1.64 1.60 ± 0.135 AUC_(0-tlast) (h*ng/mL) 17.7 17.6 21.8 19.0 ± 2.38AUC_(0-tlast)/Doseª 5.92 5.85 7.26  6.34 ± 0.793 (h*kg*ng/ml/mg)AUC_(0-inf) (h*ng/mL) 18.1 17.9 22.3 19.4 ± 2.50 MRT_(0-inf) (h) 2.041.65 1.90  1.86 ± 0.197 ^(a) C(I) dose.

TABLE 30A Plasma concentrations of psilocin following 10 mg/kg oraladministration of C(I). Experimental Plasma concentration (ng/ml) time(h) M46 M47 M48 Mean ± SD 0.25 41.5 21.0 23.8 28.8 ± 11.1 0.5 40.3 43.055.1 46.1 ± 7.88 1 22.9 25.0 32.9 26.9 ± 5.27 2 9.19 5.73 11.8 8.91 ±3.04 4 3.20 3.09 4.97 3.75 ± 1.06 6 1.63 2.35 1.13  1.70 ± 0.613 8 1.192.57 0.867  1.54 ± 0.905 24 BLQ BLQ BLQ n/a BLQ denotes below the lowerlimit of quantitation (0.2 ng/ml). n/a denotes not applicable.

TABLE 30B Summary of plasma PK parameters for psilocin following 10mg/kg oral administration of C(I)^(a). Parameter estimate for eachanimal Parameter M46 M47 M48 Mean ± SD t_(max) (h) 0.250 0.500 0.5000.417 ± 0.144 C_(max) (ng/ml) 41.5 43.0 55.1 46.5 ± 7.46C_(max)/Dose^(a) 4.15 4.30 5.51  4.65 ± 0.746 (kg*ng/ml/mg) Apparentt_(1/2) (h)^(b) 2.80 nc^(c) 1.49 2.15 (n = 2) AUC_(0-tlast) (h*ng/mL)64.6 59.2 77.9 67.2 ± 9.63 AUC_(0-tlast)/Doseª 6.46 5.92 7.79  6.72 ±0.963 (h*kg*ng/ml/mg) AUC_(0-inf) (h*ng/mL) 69.4 n/a^(d) 79.8 74.6 (n =2) MRT_(0-inf) (h) 2.45 n/a 1.91 2.18 (n = 2) ^(a)C(I) dose. ^(b)ForM46, apparent t_(1/2) estimate may not be accurate; sampling intervalduring theterminal phase <2 × t_(1/2). ^(c)nc denotes not calculable asthe terminal phase is not well defined. ^(d)n/a denotes not applicable.

TABLE 31 Comparative summary of psilocin pharmacokinetic (PK) parametersfollowing intravenous (IV) dosing of psilocybin or compound C(I)^(a).Parameter Psilocybin C(I)^(b) Nominal prodrug 1 1 dose (mg/kg) t_(max)(h)  0.139 ± 0.0962 0.0833 ± 0.00   C_(max) (ng/ml)  105 ± 19.8 22.3 ±24.9 C_(max)/Dose^(a)  105 ± 19.8 22.3 ± 24.9 (kg*ng/ml/mg) Apparentt_(1/2) (h) 0.905 (n = 1)  1.23 ± 0.349 AUC_(0-tlast) (h*ng/mL) 89.8 ±17.5 23.2 ± 21.4 AUC_(0-tlast)/Dose^(a) 89.8 ± 17.5 23.2 ± 21.4(h*kg*ng/ml/mg) AUC_(0-inf) (h*ng/mL)   110 (n = 1) 23.7 ± 21.5MRT_(0-inf) (h)  1.64 (n = 1)  1.41 ± 0.103 ^(a)C(I) dose ^(b)Values didnot exclude possible outlier M37

TABLE 32 Comparative summary of psilocin pharmacokinetic (PK) parametersfollowing oral (PO) dosing of psilocybin or compound C(I). ParameterPsilocybin C(I) Nominal prodrug dose 1 3 10 1 3 10 (mg/kg) t_(max) (h)0.333 ± 0.144 0.417 ± 0.144 0.333 ± 0.144 0.500 ± 0.00  0.417 ± 0.1440.417 ± 0.144 C_(max) (ng/mL) 53.7 ± 3.50 52.9 ± 10.5  243 ± 43.7 0.877± 0.376  2.15 ± 0.195 8.40 ± 2.17 C_(max)/Dose^(a) 1.56 17.6 ± 3.48 24.3± 4.37 0.877 ± 0.376  0.717 ± 0.0651 0.840 ± 0.217 (kg * ng/mL/mg)Apparent t_(1/2) (h) 2.15 4.51  3.58 ± 0.920 nc^(a) 3.01 1.31 (n = 1) (n= 2) (n = 1) (n = 2) AUC_(0-tlast) (h * ng/mL) 67.1 ± 1.61 84.4 ± 10.8 397 ± 55.5 1.34 ± 1.02  5.54 ± 0.330 18.7 ± 4.25 AUC_(0-tlast)/Dose^(a)34.4 ± 2.24 28.1 ± 3.61 39.7 ± 5.55 1.34 ± 1.02  1.85 ± 0.110  1.87 ±0.425 (h * kg * ng/mL/mg) AUC_(0-inf) (h * ng/mL) 70.4 80.5  398 ± 55.1n/a^(b) 6.87 20.2 (n = 1) (n = 2) (n = 1) (n = 2) MRT_(0-inf) (h) 1.532.04  2.39 ± 0.236 n/a 4.12 2.53 (n = 1) (n = 2) (n = 1) (n = 2) ^(a)ncdenotes not calculable. ^(b)n/a denotes not applicable.

TABLE 33A Summary of mean plasma exposure of psilocin as a function ofC(I) dose. C(I) dose 1 mg/kg 1 mg/kg 3 mg/kg 10 mg/kg Parameter i.v.p.o. p.o. p.o. C_(max)/Dose^(a) 22.3 ± 24.9 2.68 ± 0.117 4.21 ± 1.504.65 ± 0.746 (kg*ng/ml/mg) Apparent t_(1/2) (h)  1.23 ± 0.349 2.09 ±0.432  1.60 ± 0.135 2.15   (n = 2) AUC_(0-tlast)/Dose^(a) 23.2 ± 21.46.38 ± 1.21   6.34 ± 0.793 6.72 ± 0.963 (h*kg*ng/ml/mg)

In Vitro Survey of Pharmacological Interaction Profiles at Receptors,Transporters and Enzymes Linked to Targeted Health Conditions.

All assays were performed as described in Example 1, except compoundC(I) was used in place of C(V). To assess assay performance andestablish positive control benchmarks, ligands listed in Table 33B wereevaluated alongside test derivative. Results for all assays usingcompound C(I) or positive controls are shown in Table 33B.

TABLE 33 Data summary table of target assays for compound C(I) andcontrol ligands. Assay EC₅₀ IC₅₀ EC₅₀ IC₅₀ Target name Target type type(control) (control) (C-I) (C-I) ADRA1A GPCR AGN 5.00E−05 — >100 — ADRA1AGPCR ANT — 9.60E−04 — 6.59 ADRA2A GPCR AGN 4.00E−05 — >100 — ADRA2A GPCRANT — 3.10E−03 — 18.41 AVPR1A GPCR AGN 4.20E−04 — >100 — AVPR1A GPCR ANT— 1.60E−03 — >100 CHRM1 GPCR AGN 9.70E−03 — >100 — CHRM1 GPCR ANT —6.10E−03 — 22.89 CHRM2 GPCR AGN 2.70E−02 — >100 — CHRM2 GPCR ANT —3.20E−03 — 48.88 CNR1 GPCR AGN 1.00E−05 — 54.23 — CNR1 GPCR ANT —6.20E−04 — >100 DRD1 GPCR AGN 9.10E−02 — >100 — DRD1 GPCR ANT — 7.10E−04— 24.48 DRD2S GPCR AGN 5.10E−04 — 83.39 — DRD2S GPCR ANT — 9.60E−04 —91.12 HTR1A GPCR AGN 1.70E−03 — >100 — HTR1A GPCR ANT — 4.60E−02 — >100HTR1B GPCR AGN 9.00E−05 — 2.14 — HTR1B GPCR ANT — 5.80E−03 — >100 HTR2BGPCR AGN 6.30E−04 — >100 — HTR2B GPCR ANT — 4.00E−04 — 4.94 OPRD1 GPCRAGN 5.00E−05 — >100 — OPRD1 GPCR ANT — 5.80E−04 — >100 GABAA Ion channelOP 6.2 — >100 — GABAA Ion channel BL — 4.6 — >100 HTR3A Ion channel OP3.00E−01 — >100 — HTR3A Ion channel BL — 1.90E−03 — 7.52 MAO-A Enzyme IN— 2.90E−03 — >100 DAT transporter BL — 1.40E−03 — 42.45 NET transporterBL — 6.70E−03 — 46.99 SERT transporter BL — 1.80E−03 — >100 NMDAR Ionchannel BL — 8.00E−02 — >100 NMDAR Ion channel OP 4.40E−01 — >100 —Potency (EC₅₀ or IC₅₀) is provided in units of μM. AGN, agonist; ANT,antagonist; OP, opener; BL, blocker; IN, inhibitor.

Example 7—Synthesis and Analysis of a Seventh C₄-CarboxylicAcid-Substituted Tryptamine Derivative

The synthesis of psilocin (1) has been described previously (Shirota etal., J. Nat. Prod. 2003, 66:885-887; Kargbo et al., ACS Omega 2020,5:16959-16966). Referring to FIG. 9A, to a solution of 1 (74.7 mg, 366μmol) and N,N-Diisopropylethylamine (100 μL, 574 μmol) in DCM (2 mL) wasadded, in a dropwise manner, a solution of2,3-dihydrobenzo[b][1,4]dioxine-5-carbonyl chloride (77.2 mg, 373 μmol)in DCM (1 mL). The mixture was left to react at RT. After 3 hours themixture contained very little starting material and the reaction mixturewas poured into a separatory funnel containing 10 mL of water and 10 mLDCM. The aqueous phase was extracted with DCM (3×10 mL), all organicphases were combined, washed with brine and dried over magnesiumsulfate. After filtration the solvent was removed under reduced pressureleaving a beige solid material. The product was purified with flashchromatography (9:1 DCM:MeOH) to yield the desired product (68 mg, 51%)as a white powder. Product 2 was confirmed using the following data:MS-ESI: calculated: 367.1652. observed: 367.1651 m/z [M+H]⁺ ¹H NMR (400MHz, DMSO) δ 11.06 (s, 1H), 7.57 (dd, J=7.8, 1.6 Hz, 1H), 7.26 (dd,J=8.1, 0.8 Hz, 1H), 7.20-7.13 (m, 2H), 7.07 (t, J=7.9 Hz, 1H), 6.98 (t,J=7.9 Hz, 1H), 6.74 (dd, J=7.6, 0.8 Hz, 1H), 4.38-4.28 (m, 4H),2.79-2.71 (m, 2H), 2.44 (dd, J=9.2, 6.7 Hz, 2H), 2.01 (s, 6H). Puritywas assessed at 95%. It is noted that compound (2) in FIG. 9Acorresponds with a compound having chemical formula C(XX):

Assessment of Cell Viability Upon Treatment of a Psilocin Derivative.

Cell viability was assessed as described for Example 1, except thecompound with formula C(XX) was evaluated in place of the compound withformula C(V). Data acquired for the derivative having chemical formulaC(XX) is displayed as “C-XX” on the x-axes in FIG. 9B and FIG. 9C.

Radioligand Receptor Binding Assays.

Activity at 5-HT_(2A) receptor was assessed as described for Example 1,except the compound with formula C(XX) was evaluated in place of thecompound with formula C(V). FIG. 9D shows radioligand competition assayresults for compound with formula C(XX), depicted on the x-axis simplyas “C-XX”.

Cell Lines and Control Ligands Used to Assess Activity at 5-HT_(1A).

Cell lines, cell line maintenance, and experimental procedures assessingmodulation of 5-HT_(1A) were performed as described in Example 1, exceptthat compound C(XX) was evaluated in place of compound C(V). 5-HT_(1A)receptor binding evaluation for compound with formula C(XX) (designatedsimply “C-XX” along the x-axis) is shown in FIG. 9E. Comparison of dataacquired in +5-HT_(1A) cultures with those acquired in −5-HT_(1A)cultures suggests significant receptor modulation.

Evaluation of Metabolic Stability in Human Intestine, Liver, and SerumFractions In Vitro.

Evaluations of metabolic stability and capacity of novel molecules torelease psilocin under various in vitro conditions were performed asdescribed in Example 1, except that compound C(XX) was used in place ofcompound C(V) for all experiments. FIGS. 9F (i) and 9(F) (ii) show themetabolic stability curves for compound with formula C(XX), designated“C-XX” in assays containing HLM (Panel A), HLS9 (Panel B), HIM (PanelC), HIS9 (Panel D), AB serum (Panel E) and Buffer (Panel F).

In Vivo Evaluation of 5-HT_(2A) Receptor Agonism in Mice.

Evaluation of in vivo HTR was conducted as described in Example 1,except that compound C(XX) was used in place of compound C(V). Elevatedincidences of HTR within the defined period of monitoring was observedin (1) psilocybin-treated mice, and (2) those treated with compound“C-XX,” relative to control mice treated with i.p. injected vehicle(0.9% NaCl). These results are illustrated in FIG. 9G, wherein compoundwith formula C(XX) is designated “C-XX.”

Mouse Pharmacokinetic (PK) Evaluation of Drug Metabolism to Psilocin.

Pharmacokinetic (PK) evaluations were performed in the same manner asdescribed in Example 1, except compound C(XX) was used in place ofcompound C(V). Results for compound C(XX) PK following C(XX)administration are found in Tables 34A-34B (1 mg/kg IV dose), Tables35-35B (1 mg/kg oral dose), Tables 36A-36B (3 mg/kg oral dose), Tables37A-37B (10 mg/kg oral dose), Table 38 (C(XX) exposure), and FIG. 9H.Results for psilocin PK following C(XX) administration are found inTables 39A-39B (1 mg/kg IV dose), Tables 40A-40B (1 mg/kg oral dose),Tables 41A-41B (3 mg/kg oral dose), Tables 42A-42B (10 mg/kg oral dose),Table 43 (comparative summary for IV data), Table 44 (comparativesummary for oral data), Table 45A (psilocin exposure) and FIGS. 9I (i)-9(ii).

TABLE 34A Plasma concentrations of C(XX) following 1 mg/kg i.v.administration of C(XX). Experimental Plasma concentration (ng/ml) time(h) M49 M50 M51 Mean ± SD 0.0833 109 152 105  122 ± 26.1 0.25 66.5 84.760.3 70.5 ± 12.7 0.5 26.1 37.9 32.1 32.0 ± 5.90 1 8.93 8.13 8.22  8.43 ±0.438 2 0.968 1.03 1.14  1.05 ± 0.0871 4 0.257 0.137 0.148  0.181 ±0.0663 6 BLQ BLQ BLQ n/a 8 BLQ No No n/a Peak Peak Values in italics arebelow the lower limit of quantitation (BLQ, 0.25 ng/ml) but wereincluded in calculations. BLQ denotes below the lower limit ofquantitation (0.25 ng/ml). n/a denotes not applicable.

TABLE 34B Summary of plasma PK parameters for C(XX) following 1 mg/kgi.v. administration of C(XX). Parameter estimate for each animalParameter M49 M50 M51 Mean ± SD C₀ (ng/ml) 140 204 139  161 ± 37.3Apparent t_(1/2) (h) 0.625 0.529 0.536  0.563 ± 0.0538 AUC_(0-tlast)(h*ng/mL) 48.1 62.4 48.0 52.8 ± 8.30 AUC_(0-tlast)/Dose 48.1 62.4 48.052.8 ± 8.30 (h*kg*ng/ml/mg) AUC_(0-inf) (h*ng/mL) 48.3 62.5 48.1 53.0 ±8.26 AUC_(0-inf)/Dose 48.3 62.5 48.1 53.0 ± 8.26 (h*kg*ng/mL/mg) CL(mL/h/kg) 20692 15991 20777 19200 ± 2740  MRT_(0-inf) (h) 0.436 0.3670.429  0.411 ± 0.0379 V_(ss) (mL/kg) 9026 5874 8913 7940 ± 1790

TABLE 35A Plasma concentrations of C(XX) following 1 mg/kg oraladministration of C(XX). Experimental Plasma concentration (ng/ml) time(h) M52 M53 M54 Mean ± SD 0.25 0.701 0.459 0.648 0.603 ± 0.127  0.50.702 0.509 0.648 0.620 ± 0.0996 1 0.396 0.286 0.199 0.294 ± 0.0987 2BLQ BLQ BLQ n/a 4 BLQ BLQ BLQ n/a 6 No Peak No Peak BLQ n/a 8 No PeakBLQ No Peak n/a 24 No Peak No Peak No Peak n/a BLQ denotes below thelower limit of quantitation (0.25 ng/ml).

TABLE 35B Summary of plasma PK parameters for C(XX) following 1 mg/kgoral administration of C(XX). Parameter estimate for each animalParameter M52 M53 M54 Mean ± SD t_(max) (h) 0.500 0.500 0.250 0.417 ±0.144  C_(max) (ng/ml) 0.702 0.509 0.648 0.620 ± 0.0996 C_(max)/Dose0.702 0.509 0.648 0.620 ± 0.0996 (kg*ng/ml/mg)

TABLE 36A Plasma concentrations of C(XX) following 3 mg/kg oraladministration of C(XX). Experimental Plasma concentration (ng/ml) time(h) M55 M56 M57 Mean ± SD 0.25 1.49 1.72 1.93 1.71 ± 0.220 0.5 1.45 1.131.43 1.34 ± 0.179 1 0.430 0.752 0.535 0.572 ± 0.164  2 0.124 0.244 0.1560.175 ± 0.0621 4 No Peak BLQ No Peak n/a 6 No Peak BLQ BLQ n/a 8 No PeakBLQ BLQ n/a 24 No Peak No Peak No Peak n/a Values in italics are belowthe lower limit of quantitation (BLQ, 0.25 ng/ml) but were included incalculations. BLQ denotes below the lower limit of quantitation (0.25ng/ml). n/a denotes not applicable.

TABLE 36B Summary of plasma PK parameters for C(XX) following 3 mg/kgoral administration of C(XX). Parameter estimate for each animalParameter M55 M56 M57 Mean ± SD t_(max) (h) 0.250 0.250 0.250 0.250 ±0.00  C_(max) (ng/mL) 1.49 1.72 1.93  1.71 ± 0.220 C_(max)/Dose 0.4970.573 0.643  0.571 ± 0.0734 (kg*ng/ml/mg) Apparent t_(1/2) (h) 0.4380.669 0.481 0.529 ± 0.123 AUC_(0-tlast) (h*ng/mL) 1.22 1.48 1.42  1.37 ±0.137 AUC_(0-tlast)/Dose 0.406 0.494 0.474  0.458 ± 0.0457(h*kg*ng/ml/mg) AUC_(0-inf) (h*ng/mL) 1.30 1.72 1.53  1.51 ± 0.210AUC_(0-inf)/Dose 0.433 0.572 0.510  0.505 ± 0.0700 (h*kg*ng/mL/mg)MRT_(0-inf) (h) 0.793 1.08 0.823 0.899 ± 0.158 F(%) 0.816 1.08 0.9620.953 ± 0.132

TABLE 37A Plasma concentrations of C(XX) following 10 mg/kg oraladministration of C(XX). Experimental Plasma concentration (ng/ml) time(h) M58 M59 M60 Mean ± SD 0.25 2.99 9.12 10.3 7.47 ± 3.92 0.5 2.79 3.875.79 4.15 ± 1.52 1 1.53 1.69 2.74  1.99 ± 0.657 2 0.707 0.533 1.08 0.773± 0.279 4 0.225 BLQ 0.302 0.264 (n = 2) 6 0.524 BLQ 0.196 0.360 (n = 2)8 0.335 BLQ 0.185 0.260 (n = 2) 24 No Peak No Peak No Peak n/a Values initalics are below the lower limit of quantitation (BLQ, 0.25 ng/ml) butwere included in calculations. BLQ denotes below the lower limit ofquantitation (0.25 ng/ml). n/a denotes not applicable.

TABLE 37B Summary of plasma PK parameters for C(XX) following 10 mg/kgoral administration of C(XX). Parameter estimate for each animalParameter M58 M59 M60 Mean ± SD t_(max) (h) 0.250 0.250 0.250 0.250 ±0.00  C_(max) (ng/ml) 2.99 9.12 10.3 7.47 ± 3.92 C_(max)/Dose 0.2990.912 1.03 0.747 ± 0.392 (kg*ng/ml/mg) Apparent t_(1/2) (h)^(a) nc^(b)0.534 5.66 3.10 (n = 2) AUC_(0-tlast) (h*ng/mL) 5.65 4.99 9.16 6.60 ±2.24 AUC_(0-tlast)/Dose 0.565 0.499 0.916 0.660 ± 0.224 (h*kg*ng/ml/mg)AUC_(0-inf) (h*ng/mL) n/a^(c) 5.40 10.7 8.03 (n = 2) MRT_(0-inf) (h) n/a0.800 3.56 2.18 (n = 2) F(%)^(d) 1.07 0.941 1.73  1.24 ± 0.423 ^(a)ForM60, apparent t_(1/2) estimate may not be accurate; sampling intervalduring the terminal phase <2 × t_(1/2). ^(b)nc denotes not calculable asthe terminal phase is not well defined. ^(c)n/a denotes not applicable.^(d)AUC_(0-tlast) was used for p.o. group, thus value might beunder-estimated.

TABLE 38 Summary of mean plasma exposure of C(XX) as a function of dose.C(XX) dose Parameter 1 mg/kg i.v. 1 mg/kg p.o. 3 mg/kg p.o. 10 mg/kgp.o. C_(max)/Dose n/aª  0.620 ± 0.0996  0.571 ± 0.0734 0.747 ± 0.392(kg*ng/mL/mg) Apparent t_(1/2) (h)  0.563 ± 0.0538 nc^(b) 0.529 ± 0.1233.10 (n = 2) AUC_(0-tlast)/Dose 52.8 ± 8.30 n/a  0.458 ± 0.0457 0.660 ±0.224 (h*kg*ng/ml/mg) F(%) n/a n/a 0.953 ± 0.132  1.24 ± 0.423 ^(a)n/adenotes not applicable. ^(b)nc denotes not calculable as the terminalphase is not well defined.

TABLE 39A Plasma concentrations of psilocin following 1 mg/kg i.v.administration of C(XX). Experimental Plasma concentration (ng/ml) time(h) M49 M50 M51 Mean ± SD 0.0833 19.9 25.3 21.3 22.2 ± 2.80 0.25 23.429.4 20.4 24.4 ± 4.58 0.5 18.0 21.9 27.3 22.4 ± 4.67 1 11.4 10.2 10.3 10.6 ± 0.666 2 6.65 3.26 4.32 4.74 ± 1.73 4 0.816 0.803 0.536 0.718 ±0.158 6 0.266 0.250 0.298  0.271 ± 0.0244 8 BLQ BLQ BLQ n/a Values initalics are below the lower limit of quantitation (BLQ, 0.5 ng/ml) butwere included in calculations. BLQ denotes below the lower limit ofquantitation (0.5 ng/ml). n/a denotes not applicable.

TABLE 39B Summary of plasma PK parameters for psilocin following 1 mg/kgi.v. administration of C(XX). Parameter estimate for each animalParameter M49 M50 M51 Mean ± SD t_(max) (h) 0.250 0.250 0.500 0.333 ±0.144 C_(max) (ng/ml) 23.4 29.4 27.3 26.7 ± 3.04 C_(max)/Doseª 23.4 29.427.3 26.7 ± 3.04 (kg*ng/mL/mg) Apparent t_(1/2) (h) 0.861 1.08 1.040.993 ± 0.116 AUC_(0-tlast) (h*ng/mL) 32.2 30.2 30.4 30.9 ± 1.10AUC_(0-tlast)/Dose^(a) 32.2 30.2 30.4 30.9 ± 1.10 (h*kg*ng/ml/mg)AUC_(0-inf) (h*ng/mL) 32.5 30.6 30.8 31.3 ± 1.05 MRT_(0-inf) (h) 1.311.13 1.17  1.20 ± 0.0971

TABLE 40A Plasma concentrations of psilocin following 1 mg/kg oraladministration of C(XX). Experimental Plasma concentration (ng/mL) time(h) M52 M53 M54 Mean ± SD 0.25 20.2 6.94 6.76 11.3 ± 7.71 0.5 18.8 13.711.0 14.5 ± 3.96 1 14.0 10.5 6.59 10.4 ± 3.71 2 4.40 3.29 3.78  3.82 ±0.556 4 1.21 0.829 0.717 0.919 ± 0.258 6 0.306 0.604 0.699 0.536 ± 0.2058 0.260 0.280 0.223  0.254 ± 0.0289 24 BLQ BLQ BLQ n/a Values in italicsare below the lower limit of quantitation (BLQ, 0.5 ng/ml) but wereincluded in calculations. BLQ denotes below the lower limit ofquantitation (0.5 ng/ml). n/a denotes not applicable.

TABLE 40B Summary of plasma PK parameters for psilocin following 1 mg/kgoral administration of C(XX). Parameter estimate for each animalParameter M52 M53 M54 Mean ± SD t_(max) (h) 0.250 0.500 0.500 0.417 ±0.144 C_(max) (ng/ml) 20.2 13.7 11.0 15.0 ± 4.73 C_(max)/Dose^(a) 20.213.7 11.0 15.0 ± 4.73 (kg*ng/ml/mg) Apparent t_(1/2) (h) 1.80 1.80 1.63 1.74 ± 0.0999 AUC_(0-tlast) (h*ng/mL) 30.7 21.5 18.4 23.5 ± 6.39AUC_(0-tlast)/Dose^(a) 30.7 21.5 18.4 23.5 ± 6.39 (h*kg*ng/mL/mg)AUC_(0-inf) (h*ng/mL) 31.3 22.2 18.9 24.1 ± 6.44 MRT_(0-inf) (h) 1.642.02 2.11  1.92 ± 0.251

TABLE 41A Plasma concentrations of psilocin following 3 mg/kg oraladministration of C(XX). Experimental Plasma concentration (ng/ml) time(h) M55 M56 M57 Mean ± SD 0.25 28.7 22.0 34.7 28.5 ± 6.35 0.5 29.2 24.029.2 27.5 ± 3.00 1 13.9 21.0 14.3 16.4 ± 3.99 2 7.27 7.83 7.13  7.41 ±0.370 4 1.13 3.08 1.15 1.79 ± 1.12 6 0.786 1.28 1.14  1.07 ± 0.255 80.486 0.440 1.26 0.729 ± 0.461 24 BLQ BLQ BLQ n/a Values in italics arebelow the lower limit of quantitation (BLQ, 0.5 ng/ml) butwere includedin calculations. n/a denotes not applicable.

TABLE 41B Summary of plasma PK parameters for psilocin following 3 mg/kgoral administration of C(XX). Parameter estimate for each animalParameter M55 M56 M57 Mean ± SD t_(max) (h) 0.500 0.500 0.250 0.417 ±0.144 C_(max) (ng/ml) 29.2 24.0 34.7 29.3 ± 5.35 C_(max)/Dose^(a) 9.738.00 11.6 9.77 ± 1.78 (kg*ng/ml/mg) Apparent t_(1/2) (h)^(b) 3.29 1.46nc^(c) 2.37 (n = 2) AUC_(0-tlast) (h*ng/mL) 41.1 48.9 44.3 44.8 ± 3.94AUC_(0-tlast)/Dose^(a) 13.7 16.3 14.8 14.9 ± 1.31 (h*kg*ng/mL/mg)AUC_(0-inf) (h*ng/mL) 43.4 49.9 n/a^(d) 46.6 (n = 2) MRT_(0-inf) (h)2.10 1.99 n/a 2.04 (n = 2) ^(b)For M55, apparent t_(1/2) estimate maynot be accurate; sampling interval during the terminal phase <2 ×t_(1/2). ^(c)nc denotes not calculable as the terminal phase is not welldefined. ^(d)n/a denotes not applicable.

TABLE 42A Plasma concentrations of psilocin following 10 mg/kg oraladministration of C(XX). Experimental Plasma concentration (ng/ml) time(h) M58 M59 M60 Mean ± SD 0.25 52.6 173 120  115 ± 60.3 0.5 54.2 94.6151 99.9 ± 48.6 1 46.2 47.2 69.9 54.4 ± 13.4 2 21.7 21.3 41.9 28.3 ±11.8 4 9.58 5.07 8.73 7.79 ± 2.40 6 8.15 2.07 4.86 5.03 ± 3.04 8 5.651.72 3.69 3.69 ± 1.97 24 BLQ BLQ BLQ n/a BLQ denotes below the lowerlimit of quantitation (0.5 ng/ml). n/a denotes not applicable.

TABLE 42B Summary of plasma PK parameters for psilocin following 10mg/kg oral administration of C(XX). Parameter estimate for each animalParameter M58 M59 M60 Mean ± SD t_(max) (h) 0.500 0.250 0.500 0.417 ±0.144 C_(max) (ng/mL) 54.2 173 151  126 ± 63.2 C_(max)/Dose^(a) 5.4217.3 15.1 12.6 ± 6.32 (kg * ng/mL/mg) Apparent t_(1/2) (h)^(b) 5.25 2.563.22 3.68 ± 1.40 AUC_(0-tlast) (h * ng/mL) 138 154 220  171 ± 43.5AUC_(0-tlast)/Dose^(a) 13.8 15.4 22.0 17.1 ± 4.35 (h * kg * ng/mL/mg)AUC_(0-inf) (h * ng/mL)^(c) 181 160 237  193 ± 39.9 MRT_(0-inf) (h) 5.551.78 2.49 3.27 ± 2.01 ^(b)Apparent t_(1/2) estimate may not be accurate;sampling interval during the terminal phase <2 × t_(1/2). ^(c)For M58, %AUC extrapolated from tlast to infinity is >20% (24%), thus estimate isnot considered accurate.

TABLE 43 Comparative summary of psilocin pharmacokinetic (PK) parametersfollowing intravenous (IV) dosing of psilocybin or compound C(XX)^(a)Parameter Psilocybin C(XX) Nominal prodrug dose 1 1 (mg/kg) t_(max) (h)0.139 ± 0.0962 0.333 ± 0.144 C_(max) (ng/mL) 105 ± 19.8  26.7 ± 3.04C_(max)/Doseª (kg * ng/mL/mg) 105 ± 19.8  26.7 ± 3.04 Apparent t_(1/2)(h) 0.905 (n = 1) 0.993 ± 0.116 AUC_(0-tlast) (h * ng/mL) 89.8 ± 17.5 30.9 ± 1.10 AUC_(0-tlast)/Dose^(a) 89.8 ± 17.5  30.9 ± 1.10 (h * kg *ng/mL/mg) AUC_(0-inf) (h * ng/mL)   110 (n = 1) 31.3 ± 1.05 MRT_(0-inf)(h)  1.64 (n = 1)  1.20 ± 0.0971 ^(a)C(XX) dose was used. ^(b)nc denotesnot calculable.

TABLE 44 Comparative summary of psilocin pharmacokinetic (PK) parametersfollowing oral (PO) dosing of psilocybin or compound C(XX). ParameterPsilocybin C(XX) Nominal prodrug dose 1 3 10 1 3 10 (mg/kg) t_(max) (h)0.333 ± 0.144 0.417 ± 0.144 0.333 ± 0.144 0.417 ± 0.144 0.417 ± 0.1440.417 ± 0.144 C_(max) (ng/mL) 53.7 ± 3.50 52.9 ± 10.5  243 ± 43.7 15.0 ±4.73 29.3 ± 5.35  126 ± 63.2 C_(max)/Dose^(a) 1.56 17.6 ± 3.48 24.3 ±4.37 15.0 ± 4.73 9.77 ± 1.78 12.6 ± 6.32 (kg * ng/mL/mg) Apparentt_(1/2) (h) 2.15 4.51  3.58 ± 0.920  1.74 ± 0.0999 2.37 3.68 ± 1.40 (n= 1) (n = 2) (n = 2) AUC_(0-tlast) (h * ng/mL) 67.1 ± 1.61 84.4 ± 10.8 397 ± 55.5 23.5 ± 6.39 44.8 ± 3.94  171 ± 43.5 AUC_(0-tlast)/Dose^(a)34.4 ± 2.24 28.1 ± 3.61 39.7 ± 5.55 23.5 ± 6.39 14.9 ± 1.31 17.1 ± 4.35(h * kg * ng/mL/mg) AUC_(0-inf) (h * ng/mL) 70.4 80.5  398 ± 55.1 24.1 ±6.44 46.6  193 ± 39.9 (n = 1) (n = 2) (n = 2) MRT_(0-inf) (h) 1.53 2.04 2.39 ± 0.236  1.92 ± 0.251 2.04 3.27 ± 2.01 (n = 1) (n = 2) (n = 2)^(a)C(XX) dose was used. ^(b)nc denotes not calculable. ^(c)n/a denotesnot applicable.

TABLE 45A Summary of mean plasma exposure of psilocin as a function ofC(XX) dose. C(XX) dose 1 mg/kg 1 mg/kg 3 mg/kg 10 mg/kg Parameter i.v.p.o. p.o. p.o. C_(max)/Doseª 26.7 ± 3.04 15.0 ± 4.73  9.77 ± 1.78 12.6 ±6.32 (kg * ng/mL/mg) Apparent t_(1/2) (h) 0.993 ± 0.116 1.74 ± 0.09992.37 3.68 ± 1.40 (n = 2) AUC_(0-tlast)/Doseª 30.9 ± 1.10 23.5 ± 6.39 14.9 ± 1.31 17.1 ± 4.35 (h * kg * ng/mL/mg)

In Vitro Survey of Pharmacological Interaction Profiles at Receptors,Transporters and Enzymes Linked to Targeted Health Conditions.

All assays were performed as described for Example 1, except compoundC(XX) was used in place of CMV. To assess assay performance andestablish positive control benchmarks, ligands listed in Table 14B wereevaluated alongside test derivative. Results for all assays usingcompound C(XX) or positive controls are shown in Table 45B.

TABLE 45B Data summary table of target assays for compound C(XX) andcontrol ligands. Assay EC₅₀ IC₅₀ EC₅₀ IC₅₀ Target name Target type type(control) (control) (C-XX) (C-XX) ADRA1A GPCR AGN 5.00E−05 — >100 —ADRA1A GPCR ANT — 9.60E−04 — 5.21 ADRA2A GPCR AGN 4.00E−05 — >100 —ADRA2A GPCR ANT — 3.10E−03 — 47.93 AVPR1A GPCR AGN 4.20E−04 — >100 —AVPR1A GPCR ANT — 1.60E−03 — >100 CHRM1 GPCR AGN 9.70E−03 — >100 — CHRM1GPCR ANT — 6.10E−03 — >100 CHRM2 GPCR AGN 2.70E−02 — >100 — CHRM2 GPCRANT — 3.20E−03 — >100 CNR1 GPCR AGN 1.00E−05 — >100 — CNR1 GPCR ANT —6.20E−04 — >100 DRD1 GPCR AGN 9.10E−02 — >100 — DRD1 GPCR ANT — 7.10E−04— 11.1 DRD2S GPCR AGN 5.10E−04 — 1.72 — DRD2S GPCR ANT — 9.60E−04 — >100HTR1A GPCR AGN 1.70E−03 — 2.03 — HTR1A GPCR ANT — 4.60E−02 — >100 HTR1BGPCR AGN 9.00E−05 — 2.00E−01 — HTR1B GPCR ANT — 5.80E−03 — >100 HTR2BGPCR AGN 6.30E−04 — >100 — HTR2B GPCR ANT — 4.00E−04 — 1.60E−02 OPRD1GPCR AGN 5.00E−05 — >100 — OPRD1 GPCR ANT — 5.80E−04 — >100 GABAA Ionchannel OP 6.2 — >100 — GABAA Ion channel BL — 4.6 — >100 HTR3A Ionchannel OP 3.00E−01 — >100 — HTR3A Ion channel BL — 1.90E−03 — 3.77MAO-A Enzyme IN — 2.90E−03 — >100 DAT transporter BL — 1.40E−03 — >100NET transporter BL — 6.70E−03 — 15.04 SERT transporter BL — 1.80E−03 —14.7 NMDAR Ion channel BL — 8.00E−02 — >100 NMDAR Ion channel OP4.40E−01 — >100 — Potency (EC₅₀ or IC₅₀) is provided in units of μM.AGN, agonist; ANT, antagonist; OP, opener; BL, blocker; IN, inhibitor.

Example 8—Synthesis and Analysis of an Eighth C₄-CarboxylicAcid-Substituted Tryptamine Derivative

The synthesis of psilocin (1) has been described previously (Shirota etal., J. Nat. Prod. 2003, 66:885-887; Kargbo et al., ACS Omega 2020,5:16959-16966). Referring to FIG. 10A, a solution of (1) (600 mg, 2.94mmol) and triethylamine (823 uL, 5.87 mmol) in anhydrous DCM (29.4 mL)was cooled down to 0° C. To it was added cyclopropylacetyl chloride (813uL, 8.22 mmol, 2.8 eq) in 3 portions (1.2 eq+1.2 eq+0.4 eq; with 2 hourintervals) and the resulting mixture was warmed up to RT and stirredovernight. After 18 h, TLC (MeOH/DCM 20:80) showed full consumption ofpsilocin. The reaction was quenched with methanol (1 mL), and thevolatiles were removed in vacuo. The crude residue was directly purifiedby FC chromatography on silica gel (24 g. MeOH/DCM 0:100 to 20:80,product eluting at 15% MeOH) to afford the product as a brown oil.¹H-NMR showed co-elution of cyclopropylacetic acid with the product.This isolated material was re-dissolved in DCM (25 mL) and extractedwith sat'd aq. NaHCO₃ (1×25 mL). The aqueous layer was back extractedwith DCM (2×30 mL), washed with brine, dried over anhydrous Na₂SO₄,filtered and concentrated to afford the pure product as a light brownsolid (510 mg, 61%). Product (2) was confirmed using the following data:MS-ESI: calculated: 286.16813. observed: 287.17532 m/z [M+H]⁺. ¹H NMR(400 MHz, CDCl₃) δ 820 (s, 1H), 7.18 (dd, J=8.2, 1.0 Hz, 1H), 7.12 (dd,J=8.2, 7.5 Hz. 1H), 6.94 (dt, J=2.2, 1.0 Hz, 1H), 6.81 (dd, J=7.5, 1.0Hz, 1H), 2.98-2.86 (m. 2H), 2.64-2.55 (m, 4H), 2.30 (s, 6H), 1.32-1.17(m, 1H), 0.71-0.59 (m, 2H), 0.31 (dt, J=6.0, 4.7 Hz, 2H). Purity wasassessed at 95%. It is noted that compound (2) in FIG. 10A correspondsto a compound having chemical formula C(IV):

Assessment of Cell Viability Upon Treatment of a Psilocin Derivative.

Cell viability was assessed as described for Example 1, except thecompound with formula C(IV) was evaluated in place of the compound withformula C(V). Data acquired for the derivative having chemical formulaC(IV) is displayed as “C-IV” on the x-axes in FIG. 10B and FIG. 10C.

Radioligand Receptor Binding Assays.

Activity at 5-HT_(2A) receptor was assessed as described for Example 1,except the compound with formula C(IV) was evaluated in place of thecompound with formula C(V). FIG. 10D shows radioligand competition assayresults for compound with formula C(IV), depicted on the x-axis simplyas “C-IV”.

Cell Lines and Control Ligands Used to Assess Activity at 5-HT_(1A).

Cell lines, cell line maintenance, and experimental procedures assessingmodulation of 5-HT_(1A) were performed as described in Example 1, exceptthat compound C(IV) was evaluated in place of compound C(V). 5-HT_(1A)receptor binding evaluation for compound with formula C(IV) (designatedsimply “C-IV” along the x-axis) is shown in FIG. 10E. Comparison of dataacquired in +5-HT_(1A) cultures with those acquired in −5-HT_(1A)cultures suggests significant receptor modulation.

Evaluation of Metabolic Stability in Human Intestine, Liver, and SerumFractions In Vitro.

Evaluations of metabolic stability and capacity of novel molecules torelease psilocin under various in vitro conditions were performed asdescribed in Example 1, except that compound C(IV) was used in place ofcompound C(V) for all experiments. FIGS. 10F (i) and 10F (ii) show themetabolic stability curves for compound with formula C(IV), designated“C-IV” in assays containing HLM (Panel A), HLS9 (Panel B), HIM (PanelC), HIS9 (Panel D), AB serum (Panel E) and Buffer (Panel F).

In Vivo Evaluation of 5-HT_(2A) Receptor Agonism in Mice.

Evaluation of in vivo HTR was conducted as described in Example 1,except that compound C(IV) was used in place of compound C(V). Elevatedincidences of HTR within the defined period of monitoring was observedin (1) psilocybin-treated mice, and (2) those treated with compound“C-IV,” relative to control mice treated with i.p. injected vehicle(0.9% NaCl). These results are illustrated in FIG. 10G, wherein compoundwith formula C(IV) is designated “C-IV.” Results for control miceinjected with vehicle are not shown in FIG. 10G, but are the same asthose in Examples 1 and 2 since HTR experiments were run with the samecontrol cohorts.

Mouse Pharmacokinetic (PK) Evaluation of Drug Metabolism to Psilocin.

Pharmacokinetic (PK) evaluations were performed in the same manner asdescribed in Example 1, except compound C(IV) was used in place ofcompound C(V). Notably, compound C(IV) was not detectable in any animalsat any dose, suggesting a degree of instability and/or quick conversionto psilocin. Thus, only psilocin PK analysis was performed. Furthermore,“measured” concentrations of C(IV) dosing solutions were used in placeof “nominal” concentrations, to minimize variance owing to compoundinstability in dosing solutions. Table 46 summarizes these “measured”concentrations along with corresponding “nominal” concentrations foreach dosing solution. Results for psilocin PK following C(IV)administration are found in Tables 47A-47B (0.293 mg/kg IV dose), Tables48A-48B (0.275 mg/kg oral dose), Tables 49A-49B (0.789 mg/kg oral dose),Tables 50A-50B (2.52 mg/kg oral dose), Table 51 (comparative summary forIV data), Table 52 (comparative summary for oral data), Table 53A(psilocin exposure) and FIGS. 10H (i) and 10H (ii).

TABLE 46  C(IV) and psilocin residual dosing solution concentrations^(a). C(IV), C(IV), C(IV), Psilocin^(b), nominal measured administeredmeasured (mg/mL) (mg/mL) dose^(c) (mg/kg) (mg/mL) 0.2 0.0586 0.2930.00324  0.1 0.0275 0.275 0.00174^(d) 0.3 0.0789 0.789 0.00474  1 0.2522.52 0.0234   ^(a) C(IV) dosing solutions were diluted 4000-fold priorto analysis. ^(b)Psilocin was also observed in the bioanalyticalstandard ^(c)Administered dose (measured concentration * dose volume).^(d)Levels are not accurate as psilocin peak areas in the dosingsolution were below the lower limit of quantitation; shown for referenceonly.

TABLE 47A Plasma concentrations of psilocin following 0.293 mg/kg i.v.administration of C(IV). Experimental Plasma concentration (ng/ml) time(h) M61 M62 M63 Mean ± SD 0.0833 20.5 148 23.8 64.1 ± 72.7 0.25 9.3357.1 11.1 25.8 ± 27.1 0.5 4.74 18.8 4.68 9.41 ± 8.13 1 1.74 4.66 2.522.97 ± 1.51 2 0.932 3.55 0.747 1.74 ± 1.57 4 0.450 0.622 0.181 0.418 ±0.222 6 0.149 0.308 0.134  0.197 ± 0.0964 8 No Peak BLQ BLQ n/a BLQdenotes below the lower limit of quantitation (0.2 ng/ml). Values initalics are below the lower limit of quantitation (BLQ, 0.2 ng/ml) butwere included in calculations. n/a denotes not applicable.

TABLE 47B Summary of plasma PK parameters for psilocin following 0.293mg/kg i.v. administration of C(IV). Parameter estimate for each animalParameter M61 M62 M63 Mean ± SD t_(max) (h) 0.0833 0.0833 0.0833 0.0833± 0.00  C_(max) (ng/mL) 20.5 148 23.8 64.1 ± 72.7 C_(max)/Doseª 70.0 50581.2 219 ± 248 (kg * ng/mL/mg) Apparent t_(1/2) (h) 1.51 1.13 1.61  1.42± 0.253 AUC_(0-tlast) 9.57 44.1 9.94 21.2 ± 19.8 (h * ng/mL)AUC_(0-tlast)/Doseª 32.7 151 33.9 72.4 ± 67.7 (h * kg * ng/mL/mg)AUC_(0-inf) 9.90 44.6 10.3 21.6 ± 19.9 (h * ng/mL) MRT_(0-inf) (h) 1.320.738 1.06  1.04 ± 0.292 ^(a)C(IV) measured dose of 0.293 mg/kg(measured concentration * dose volume) was used.

TABLE 48A Plasma concentrations of psilocin following 0.275 mg/kg oraladministration of C(IV). Experimental Plasma concentration (ng/mL) time(h) M64 M65 M66 Mean ± SD 0.25 5.39 10.0 9.62 8.33 ± 2.56  0.5 4.88 6.053.61 4.85 ± 1.22  1 2.94 4.50 1.50 2.98 ± 1.50  2 0.851 0.862 0.8270.847 ± 0.0179 4 0.233 0.254 BLQ 0.244 ± 0.0148 6 0.166 0.106 BLQ 0.136(n = 2) 8 BLQ 0.109 BLQ 0.109 (n = 1) 24 No Peak No Peak No Peak n/a BLQdenotes below the lower limit of quantitation (0.2 ng/ml). Values initalics are below the lower limit of quantitation (BLQ, 0.2 ng/ml) butwere included in calculations. n/a denotes not applicable.

TABLE 48B Summary of plasma PK parameters for psilocin following 0.275mg/kg oral administration of C(IV). Parameter estimate for each animalParameter M64 M65 M66 Mean ± SD t_(max) (h) 0.250 0.250 0.250 0.250 ±0.00  C_(max) (ng/mL) 5.39 10.0 9.62 8.34 ± 2.56 C_(max)/Dose^(a) 19.636.4 35.0 30.3 ± 9.31 (kg * ng/mL/mg) Apparent t_(1/2) (h) 1.70 1.960.748  1.47 ± 0.637 AUC_(0-tlast) 6.91 9.58 5.07 7.19 ± 2.27 (h * ng/mL)AUC_(0-tlast)/Dose^(a) 25.1 34.9 18.4 26.1 ± 8.26 (h * kg * ng/mL/mg)AUC_(0-inf) 7.31 9.89 5.96 7.72 ± 2.00 (h * ng/mL) MRT_(0-inf) (h) 1.701.54 1.02  1.42 ± 0.356 ^(a)C(IV) measured dose of 0.275 mg/kg (measuredconcentration * dose volume) was used.

TABLE 49A Plasma concentrations of psilocin following 0.789 mg/kg oraladministration of C(IV). Experimental Plasma concentration (ng/mL) time(h) M67 M68 M69 Mean ± SD 0.25 8.80 10.1 12.4 10.4 ± 1.82  0.5 16.2 8.3512.6 12.4 ± 3.93  1 4.32 4.90 4.55 4.59 ± 0.292 2 1.46 1.97 1.84 1.76 ±0.265 4 0.356 0.354 0.393 0.368 ± 0.0220 6 0.120 0.140 0.178 0.146 ±0.0295 8 0.118 0.126 BLQ 0.122 (n = 2) 24 No Peak No Peak No Peak n/aBLQ denotes below the lower limit of quantitation (0.2 ng/ml). Values initalics are below the lower limit of quantitation (BLQ, 0.2 ng/ml) butwere included in calculations. n/a denotes not applicable.

TABLE 49B Summary of plasma PK parameters for psilocin following 0.789mg/kg oral administration of C(IV). Parameter estimate for each animalParameter M67 M68 M69 Mean ± SD t_(max) (h) 0.500 0.250 0.500 0.417 ±0.144 C_(max) (ng/mL) 16.2 10.1 12.6 13.0 ± 3.07 C_(max)/Dose^(a) 20.512.8 16.0 16.4 ± 3.89 (kg * ng/mL/mg) Apparent t_(1/2) (h) 1.61 1.511.19  1.43 ± 0.219 AUC_(0-tlast) 13.6 12.6 14.0  13.4 ± 0.723 (h *ng/mL) AUC_(0-tlast)/Dose^(a) 17.2 16.0 17.8  17.0 ± 0.916 (h * kg *ng/mL/mg) AUC_(0-inf) 13.9 12.9 14.3  13.7 ± 0.736 (h*ng/mL) MRT_(0-inf)(h) 1.39 1.56 1.31  1.42 ± 0.128 ^(a)C(IV) measured dose of 0.789 mg/kg(measured concentration * dose volume) was used.

TABLE 50A Plasma concentrations of psilocin following 2.52 mg/kg oraladministration of C(IV). Experimental Plasma concentration (ng/ml) time(h) M70 M71 M72 Mean ± SD 0.25 58.5 47.6 51.8 52.6 ± 5.50  0.5 44.3 33.952.2 43.5 ± 9.18  1 31.8 15.8 18.7 22.1 ± 8.52  2 5.54 4.10 7.20 5.61 ±1.55  4 1.03 0.758 1.19 0.993 ± 0.218  6 0.375 0.397 0.372 0.381 ±0.0137 8 0.256 0.188 0.184 0.209 ± 0.0405 24 BLQ No Peak No Peak n/a BLQdenotes below the lower limit of quantitation (0.2 ng/ml). Values initalics are below the lower limit of quantitation (BLQ, 0.2 ng/ml) butwere included in calculations. n/a denotes not applicable.

TABLE 50B Summary of plasma PK parameters for psilocin following 2.52mg/kg oral administration of C(IV). Parameter estimate for each animalParameter M70 M71 M72 Mean ± SD t_(max) (h) 0.250 0.250 0.500 0.333 ±0.144 C_(max) (ng/ml) 58.5 47.6 52.2 52.8 ± 5.47 C_(max)/Dose^(a) 23.218.9 20.7 20.9 ± 2.17 (kg * ng/mL/mg) Apparent t_(1/2) (h) 1.99 1.991.49  1.82 ± 0.291 AUC_(0-tlast) 61.2 42.2 56.5 53.3 ± 9.90 (h * ng/mL)AUC_(0-tlast)/Doseª 24.3 16.7 22.4 21.2 ± 3.93 (h * kg * ng/mL/mg)AUC_(0-inf) 62.0 42.7 56.9 53.9 ± 9.96 (h * ng/mL) MRT_(0-inf) (h) 1.201.21 1.19  1.20 ± 0.0102 ^(a)C(IV) measured dose of 2.52 mg/kg (measuredconcentration * dose volume) was used.

TABLE 51 Psilocin PK parameters following IV prodrug dosing. ParameterPsilocybin C(IV) Prodrug nominal 1 1 dose (mg/kg) Prodrug measured 10.293 dose (mg/kg)ª t_(max) (h)  0.139 ± 0.0962 0.0833 ± 0.00  C_(max)(ng/mL) 105 ± 19.8 64.1 ± 72.7 C_(max)/Dose^(b) _(nominal) 105 ± 19.864.1 ± 72.7 (kg * ng/mL/mg) C_(max)/Dose^(b) _(measured) 105 ± 19.8 219± 248 (kg * ng/mL/mg) Apparent t_(1/2) (h) 0.905 (n = 1)  1.42 ± 0.253AUC_(0-tlast) 89.8 ± 17.5 21.2 ± 19.8 (h * ng/mL) AUC_(0-tlast)/ 89.8 ±17.5 21.2 ± 19.8 Dose^(b) _(nominal) (h * kg*ng/mL/mg) AUC_(0-tlast)/89.8 ± 17.5 72.4 ± 67.7 Dose^(b) _(measured) (h * kg * ng/mL/mg)AUC_(0-inf) (h * ng/mL)  110 (n = 1) 21.6 ± 19.9 MRT_(0-inf) (h) 1.64 (n= 1)  1.04 ± 0.292

TABLE 52 Psilocin PK parameters following oral prodrug dosing. ParameterPsilocybin C(IV) Prodrug nominal dose 1 3 10 1 3 10 (mg/kg) Prodrugmeasured dose 1.56 3 10 0.275 0.789 2.52 (mg/kg)^(a) t_(max) (h) 0.333 ±0.144 0.417 ± 0.144 0.333 ± 0.144 0.250 ± 0.00  0.417 ± 0.144 0.333 ±0.144 C_(max) (ng/mL) 53.7 ± 3.50 52.9 ± 10.5  243 ± 43.7 8.34 ± 2.5613.0 ± 3.07 52.8 ± 5.47 C_(max)/Dose^(b) _(nominal) 1.56 17.6 ± 3.4824.3 ± 4.37 0.275 4.32 ± 1.02  5.28 ± 0.547 (kg * ng/mL/mg)C_(max)/Dose^(b) _(measured) 34.4 ± 2.24 17.6 ± 3.48 24.3 ± 4.37 30.3 ±9.31 16.4 ± 3.89 20.9 ± 2.17 (kg * ng/mL/mg) Apparent t_(1/2) (h) 2.154.51  3.58 ± 0.920  1.47 ± 0.637  1.43 ± 0.219  1.82 ± 0.291 (n = 1) (n= 2) AUC_(0-tlast) (h * ng/mL) 67.1 ± 1.61 84.4 ± 10.8  397 ± 55.5 7.19± 2.27  13.4 ± 0.723 53.3 ± 9.90 AUC_(0-tlast)/Dose^(b) _(nominal) 34.4± 2.24 28.1 ± 3.61 39.7 ± 5.55 30.3 ± 9.31  4.47 ± 0.241  5.33 ± 0.990(h * kg * ng/mL/mg) AUC_(0-tlast)/Dose^(b) _(measured) 43.0 ± 1.03 28.1± 3.61 39.7 ± 5.55 26.1 ± 8.26  17.0 ± 0.916 21.2 ± 3.93 (h * kg *ng/mL/mg) AUC_(0-inf) (h * ng/mL) 70.4 80.5  398 ± 55.1 7.72 ± 2.00 13.7 ± 0.736 53.9 ± 9.96 (n = 1) (n = 2) MRT_(0-inf) (h) 1.53 2.04 2.39 ± 0.236  1.42 ± 0.356  1.42 ± 0.128  1.20 ± 0.0102 (n = 1) (n = 2)

TABLE 53A Summary of mean plasma exposure of psilocin as a function ofC(IV) dose. C(IV) dose 0.293 0.275 0.789 2.52 mg/kg mg/kg mg/kg mg/kgParameter i.v. p.o. p.o. p.o. C_(max)/Doseª 219 ± 30.3 ± 16.4 ± 20.9 ±(kg * ng/mL/mg) 248 9.31 3.89 2.17 Apparent t_(1/2) (h) 1.42 ± 1.47 ±1.43 ± 1.82 ± 0.253 0.637 0.219 0.291 AUC_(0-tlast)/Doseª 72.4 ± 26.1 ±17.0 ± 21.2 ± (h * kg * ng/mL/mg) 67.7 8.26 0.916 3.93

In Vitro Survey of Pharmacological Interaction Profiles at Receptors,Transporters and Enzymes Linked to Targeted Health Conditions.

All assays were performed as described for Example 1, except compoundC(IV) was used in place of CMV. To assess assay performance andestablish positive control benchmarks, ligands listed in Table 14B wereevaluated alongside test derivative. Results for all assays usingcompound C(IV) or positive controls are shown in Table 53B.

TABLE 53B Data summary table of target assays for compound C(IV) andcontrol ligands. Assay EC₅₀ IC₅₀ EC₅₀ IC₅₀ Target name Target type type(control) (control) (C-IV) (C-IV) ADRA1A GPCR AGN 5.00E−05 — >100 —ADRA1A GPCR ANT — 9.60E−04 — 26.39 ADRA2A GPCR AGN 4.00E−05 — >100 —ADRA2A GPCR ANT — 3.10E−03 — >100 AVPR1A GPCR AGN 4.20E−04 — >100 —AVPR1A GPCR ANT — 1.60E−03 — >100 CHRM1 GPCR AGN 9.70E−03 — >100 — CHRM1GPCR ANT — 6.10E−03 — >100 CHRM2 GPCR AGN 2.70E−02 — >100 — CHRM2 GPCRANT — 3.20E−03 — >100 CNR1 GPCR AGN 1.00E−05 — >100 — CNR1 GPCR ANT —6.20E−04 — >100 DRD1 GPCR AGN 9.10E−02 — >100 — DRD1 GPCR ANT — 7.10E−04— 32.89 DRD2S GPCR AGN 5.10E−04 — 1.4 — DRD2S GPCR ANT — 9.60E−04 — >100HTR1A GPCR AGN 1.70E−03 — 5.56 — HTR1A GPCR ANT — 4.60E−02 — >100 HTR1BGPCR AGN 9.00E−05 — 2.70E−02 — HTR1B GPCR ANT — 5.80E−03 — >100 HTR2BGPCR AGN 6.30E−04 — >100 — HTR2B GPCR ANT — 4.00E−04 — 5.90E−02 OPRD1GPCR AGN 5.00E−05 — 37.84 — OPRD1 GPCR ANT — 5.80E−04 — >100 GABAA Ionchannel OP 6.2 — >100 — GABAA Ion channel BL — 4.6 — >100 HTR3A Ionchannel OP 3.00E−01 — >100 — HTR3A Ion channel BL — 1.90E−03 — 76.66MAO-A Enzyme IN — 2.90E−03 — 34.36 DAT transporter BL — 1.40E−03 — >100NET transporter BL — 6.70E−03 — >100 SERT transporter BL — 1.80E−03 —67.95 NMDAR Ion channel BL — 8.00E−02 — >100 NMDAR Ion channel OP4.40E−01 — >100 — Potency (EC₅₀ or IC₅₀) is provided in units of μM.AGN, agonist; ANT, antagonist; OP, opener; BL, blocker; IN, inhibitor.

1. A chemical compound having chemical formula (I):

wherein R₄ is a carboxylic acid moiety or a derivative thereof; whereinR_(3a) and R_(3b) are each independently a hydrogen atom, an alkylgroup, or an aryl group; and wherein the carboxylic acid moiety orderivative thereof has the chemical formula (II):

wherein R_(4a) is (i) a substituted phenyl group, wherein the phenylgroup is substituted with one or more O-alkyl groups, or (ii)substituted alkyl group, wherein the substituted alkyl group is—CH₂-cyclopropane. 2-7. (canceled)
 8. A chemical compound according toclaim 1, wherein the O-alkyl group is a methoxy group, an ethoxy group,a propoxy group, an iso-propoxy group, or a butoxy group (n-but, s-butor t-but).
 9. A chemical compound according to claim 1, wherein theO-alkylated phenyl group is O-alkylated by one or more methoxy groups.10. A chemical compound according to claim 1, wherein R_(3a) and R_(3b)are each independently a C₁-C₆ alkyl group.
 11. A chemical compoundaccording to claim 1, wherein each R_(3a) and R_(3b) are a methyl group.12. A chemical compound according to claim 1, wherein one of R_(3a) andR_(3b) is a C₁-C₆ alkyl group, and the other of R_(3a) and R_(3b) is ahydrogen atom.
 13. A chemical compound according to claim 1, wherein inthe compound having chemical formula (I) the compound is selected fromC(IV) and C(V):


14. A pharmaceutical formulation comprising a chemical compoundaccording to claim 1, together with a pharmaceutically acceptableexcipient, diluent, or carrier.
 15. A pharmaceutical formulationcomprising a chemical compound according to claim 13, together with apharmaceutically acceptable excipient, diluent, or carrier.
 16. Apharmaceutical formulation according to claim 14, wherein thepharmaceutical formulation is a pro-drug pharmaceutical formulation,wherein the compound having formula (I) is in vivo hydrolyzed to form acompound having chemical formula (VI):

wherein R_(3a) and R_(3b) are each independently a hydrogen atom, analkyl group, or an aryl group.
 17. A method for treating a brainneurological disorder, the method comprising administering to a subjectin need thereof a pharmaceutical formulation comprising a chemicalcompound according to claim 1, wherein the pharmaceutical formulation isadministered in an effective amount to treat the brain neurologicaldisorder in the subject.
 18. A method according to claim 17, whereinupon administration the compound having formula (I) interacts with areceptor in the subject to thereby modulate the receptor and exert apharmacological effect.
 19. A method according to claim 18, wherein thereceptor is a 5-HT_(1A) receptor, a 5-HT_(2A) receptor, a 5-HT_(1B)receptor, a 5-HT_(2B) receptor, a 5-HT_(3A) receptor, an ADRA1Areceptor, an ADRA2A receptor, CHRM1 receptor, a CHRM2 receptor, a CNR1receptor, a DRD1 receptor, a DRD2S receptor, or an OPRD1 receptor.
 20. Amethod according to claim 17, wherein upon administration the compoundhaving formula (I) interacts with an enzyme or transmembrane transportprotein in the subject to thereby modulate the enzyme or transmembranetransport protein and exert a pharmacological effect.
 21. A methodaccording to claim 20, wherein the enzyme is monoamine oxidase A(MOA-A), and the transmembrane transport protein is a dopamine activetransporter (DAT), or a norephedrine transporter (NET) or a serotonintransporter (SERT) transmembrane transport protein.
 22. A methodaccording to claim 17, wherein upon administration the compound havingformula (I) is in vivo hydrolyzed to form a compound having chemicalformula (VI):

wherein R_(3a) and R_(3b) are each independently a hydrogen atom, analkyl group, or an aryl group, and wherein the compound having chemicalformula (VI) interacts with a receptor to thereby modulate the receptorin the subject and exert a pharmacological effect.
 23. A methodaccording to claim 17, wherein the receptor is 5-HT_(1A) receptor, a5-HT_(2A) receptor, a 5-HT_(1B) receptor, a 5-HT_(2B) receptor, a5-HT_(3A) receptor, an ADRA1A receptor, an ADRA2A receptor, a CHRM1receptor, a CHRM2 receptor, a CNR1 receptor, a DRD1 receptor, a DRD2Sreceptor, or an OPRD1 receptor.
 24. A method according to claim 17,wherein the disorder is a 5-HT_(1A) receptor-mediated disorder, a5-HT_(2A) receptor-mediated disorder, a 5-HT_(1B) receptor-mediateddisorder, a 5-HT_(2B) receptor-mediated disorder, a 5-HT_(3A)receptor-mediated disorder, an ADRA1A receptor-mediated disorder, anADRA2A receptor-mediated disorder, a CHRM1 receptor-mediated disorder, aCHRM2 receptor-mediated disorder, a CNR1 receptor-mediated disorder, aDRD1 receptor-mediated disorder, a DRD2S receptor-mediated disorder, oran OPRD1 receptor-mediated disorder.
 25. A method according to claim 17,wherein a dose is administered of about 0.001 mg to about 5,000 mg. 26.A method for treating a brain neurological disorder, the methodcomprising administering to a subject in need thereof a pharmaceuticalformulation comprising a chemical compound according to claim 13,wherein the pharmaceutical formulation is administered in an effectiveamount to treat the brain neurological disorder in the subject.
 27. Amethod according to claim 26, wherein upon administration the compoundhaving formula (I) interacts with a receptor in the subject to therebymodulate the receptor and exert a pharmacological effect.
 28. A methodaccording to claim 27, wherein the receptor is a 5-HT_(1A) receptor, a5-HT_(2A) receptor, a 5-HT_(1B) receptor, a 5-HT_(2B) receptor, a5-HT_(3A) receptor, an ADRA1A receptor, an ADRA2A receptor, CHRM1receptor, a CHRM2 receptor, a CNR1 receptor, a DRD1 receptor, a DRD2Sreceptor, or an OPRD1 receptor.
 29. A method according to claim 26,wherein upon administration the compound having formula (I) interactswith an enzyme or transmembrane transport protein in the subject tothereby modulate the enzyme or transmembrane transport protein and exerta pharmacological effect.
 30. A method according to claim 29, whereinthe enzyme is monoamine oxidase A (MOA-A), and the transmembranetransport protein is a dopamine active transporter (DAT), or anorephedrine transporter (NET) or a serotonin transporter (SERT)transmembrane transport protein.
 31. A method according to claim 26,wherein upon administration the compound having formula (I) is in vivohydrolyzed to form a compound having chemical formula (VI):

wherein R_(3a) and R_(3b) are each independently a hydrogen atom, analkyl group, or an aryl group, and wherein the compound having chemicalformula (VI) interacts with a receptor to thereby modulate the receptorin the subject and exert a pharmacological effect.
 32. A methodaccording to claim 26, wherein the receptor is 5-HT_(1A) receptor, a5-HT_(2A) receptor, a 5-HT_(1B) receptor, a 5-HT_(2B) receptor, a5-HT_(3A) receptor, an ADRA1A receptor, an ADRA2A receptor, a CHRM1receptor, a CHRM2 receptor, a CNR1 receptor, a DRD1 receptor, a DRD2Sreceptor, or an OPRD1 receptor.
 33. A method according to claim 26,wherein the disorder is a 5-HT_(1A) receptor-mediated disorder, a5-HT_(2A) receptor-mediated disorder, a 5-HT_(1B) receptor-mediateddisorder, a 5-HT_(2B) receptor-mediated disorder, a 5-HT_(3A)receptor-mediated disorder, an ADRA1A receptor-mediated disorder, anADRA2A receptor-mediated disorder, a CHRM1 receptor-mediated disorder, aCHRM2 receptor-mediated disorder, a CNR1 receptor-mediated disorder, aDRD1 receptor-mediated disorder, a DRD2S receptor-mediated disorder, oran OPRD1 receptor-mediated disorder.
 34. A method according to claim 26,wherein a dose is administered of about 0.001 mg to about 5,000 mg.